My understanding is that the sheen/finish does in fact play a part in how much light is reflected and so does the LRV, depending on the color. So if we have a high LRV the more sheen we have the more imperfections will show ~ is this a correct assumption?

No.

Gloss (specular reflectance) is independent from LRV (light/luminance reflectance).

Even subltly shiny paint film will highlight wall imperfections. But LRV has nothing to do with it.

LRV is measured luminance (of a color) expressed as a percentage on a scale from 0 to 100. LRV tells you how much light a color reflects. That's all it does. It has one job.

There are many youtube videos comparing the two and explaining the abilities of the "one coat" cover for each brand but nothing that I have found conclusive.

Because it (mostly) depends on the color. Every brand has colors that have decent hide in one coat and colors that require as many as 3+.

Behr is the big box paint for the DIY’er and it does not make sense to use it if you are hiring a painter.

I know pro painters that use BEHR. I don't specify it and I wouldn't choose it for my own house but a lot of people like it.

SW’s mixing of colors is more scientifically advanced, done in a factory.

This is ridiculous - just no.

Paint colors from all brands - globally - are born in the exact same theoretical color space and every brand uses the exact same color science to develop paint color formulas.

There is no significant difference in the consistency. Behr in some cases goes on thicker and clumped and shows roller marks. In other cases it is because of the application process.

It all depends on who's applying it and on what substrate. If they have to and they're getting paid enough, a skilled painter can make the crappiest can of paint look like a million bucks when done.

I never tell a painter what to use. Especially exterior. It's worth it to find a way to make their preferred brand work if at all possible with the provision that it has to be an upper grade of paint.

SWs will always look smoother with less roller lines, is this true OR more about the skill of the painter?

See previous answer.

Priming is essential no matter which paint is used.

No. The purpose of priming is to prepare the surface for the NEW coats of paint - if needed. For example, if there's something going on with the substrate that needs repaired/sealed. Or if the new color has poor hide and needs an undercoat of color to reach opacity.

Behr is more limited in paint color variety, very limited in whites offered.

Not true. Behr actually has a decent color selection. It's just their color tools and collections are a hot mess of frenetic and chaos.

Does one brand make it easier to do touch ups in the future?

A dampened sponge brush and several light coats is how you attempt touch ups. Benjamin Moore Aura matte touches up the easiest. SW Cashmere fairs well too. Lighter colors with less colorants usually touch up the easiest - IME and IMO.

Does SW’s guarantee make it worth the extra expense?

Yes. I'd choose SW Cashmere in lo-lustre. Because I don't like the final finish you get with BEHR. I think it has a plastic-y, hi-resin look and feel. Of course, YMMV.

There is soooo much written about what brand of paint to use. I have a 30 year old home and in the last 2 years I had my kitchen and bathrooms, flooring and lighting, all redone. I chose each craftsman after researching and interviewing them too. I had high end custom cabinetry and a new oak staircase with bannister installed and matched the stain perfectly to my Italian porcelain wood look tile flooring.
Husband and I fixed all wall and ceiling nail pops and cracks, primed areas of repair, sanded all moldings and doors, and washed and rinsed all ceilings and walls, doors and moldings; as prep work is key to any good paint job.
Husband and I are perfectionists when it comes to painting.
We painted our entire home with Behr paint. We used top of the line brushes and rollers.
For all walls we used: Behr Ultra Scuff Defense stain blocking paint & primer flat paint. For all doors and moldings we used Behr Ultra Scuff Defense stain blocking & primer satin paint. For all ceilings we used Behr Ultra stain blocking paint and primer ceiling flat paint.
We took our time as I am semi retired and my husband is retired.
Our paint job came out quite beautiful.
The Behr paint was wonderful to apply.
No professional painter would have ever done the complete prep work we did, or beautiful paint job we did.
We have used SW and BM paints in previous homes as well as Behr paint. I like the Behr the best.
I couldn’t be more pleased with Behr paint❣️

@Lori A. Sawaya I know it’s been a while since this post, but sooooo much happened with our renovation project just after I wrote this that we haven’t been ready until now to consider paint. That said, we appreciate the thoroughness with which you responded and it was very helpful in our interviewing of painters . It seems so subjective and each and everyone has their own way of doing things. But your words of wisdom were definitely helpful. You really clarified a bunch of the things we had questions about. Grateful again for you taking the time to read and respond.

You're welcome. Glad I could help.

@kculbers

This response is well over do. Our renovation took an unexpected turn and we weren’t even able to consider paint until now. Thanks for your response. . .

Wow, what a job to take on. We are very impressed and would love to ask you about some things as we are seriously considering, after getting all of the estimates, to do the job ourselves. You have definitely inspired us to try at least one room and go from there. We are not in a rush so we too, can take our time. We’d like to get more details, though, on how you and your husband prepared and then proceeded to paint the walls, ceiling, doors, and trim.

Might we pick your brain?

Did you wash the walls, ceilings, trim, doors and moldings with anything other than water and/or mild soap?

Do you have any issues with flat paint and wiping or washing the walls?

You mentioned you used top of the line, brushes and rollers. Are there any specific brands you would recommend?

Hi humming_bird333❣️When we fixed our cracks in the drywall: we used Dap spackling for small cracks and Bondo body filler (for cars) for larger cracks. My husband has restored cars in the past and was quite familiar with Bondo use. Our carpenter had recommended we use Bondo for large cracks. After we repaired cracks and nail pops, we sanded areas and washed with diluted Palmolive dish soap and rinsed with water. All repaired areas were primed with Kilz 2 All Purpose Primer. We had no issues washing and rinsing walls and ceilings with diluted Palmolive. Take your time so you do a good job. For paint rollers we used Wooster and Purdy White Dove 9” rollers with 3/8” nap as we have smooth drywall. For small areas we used 4 and 6” small rollers. We used Wooster roller frames. We also used various sizes of Wooster Pro paint brushes. I can’t emphasize enough to take your time. If you are tired stop and rest. You will do your best work when you are alert and not tired. Buy some good plastic sheeting to cover your furniture and plenty of paint cloth for your floors. I purchased most of my paint supplies from Home Depot as I got a 10% military discount ( I am a retired US Air Force Captain). Paint ceilings, then walls then moldings. I saved painting all my doors for last. Remember to also paint the insides of all closets❣️Best of luck to you on your painting journey.

@kculbers Thanks for all the great advice and tips. We've actually started gathering our supplies for the project and your recommendations were so helpful as we found ourselves in awe of the many choices out there for ie. rollers, paint brushes etc. We were able to narrow in on the good quality tools and save ourselves lots of time trying to figure it all out on our own. We get that prep is the most important and plan to take our time with this part of the project. Thanks again for taking the time out to give us details. We will let you know how it goes.

Humming_bird333: I am so glad my information was helpful to you❣️I have been helped by the Houzz community so many times ; I am happy I could offer my experience. Let us know how your project goes.