To be honest, I had to google it

The Difference Between Clear Glass & Low-Iron Glass

The difference between clear glass and low-iron glass is the greater transparency of the latter, making it more ideal for certain uses such as frameless glass walls, display cases, partitions and dividers, and other appearance-driven applications.

i have what im guessing is regular glass on all of my showers and it looks beautifully clear. Im not sure that I would upgrade. I did however, ceramic coat my glass. Its supposed to be like rainex on steroids and much longer lasting. Keeping your glass spotless is what makes them beautiful. Im guessing the low iron glass isnt resistant to spots and what not.

I did the regular clear glass in 2 bathrooms with the rain-x coating and am happy with them. If money is not a concern at all for you, go with the low-iron glass, but IMO the clear is totally fine and saves $$.

I should have added some pics. See below for the 2 bathrooms:

Here’s one of mine with regular clear glass (ignore the fact that it’s not cleaned!)

I think you bathroom and glass door looks great. I honestly can't tell the difference. But for whatever reason my contractor is highly recommending.

The difference is in a slight green tint in regular glass when viewed at certain angles. If my upsell had been double, I would’ve passed- but I think it was only 25% additional.

I remodeled my master bath last year. It was the fourth bathroom we remodeled (others were in our previous house). I'm pretty sure this one has regular glass because it has a noticable green tint. The shower tile is white. However, the walls are painted a pale green, so it doesn't look bad. I think with a different color tile it wouldn't be as noticable. But if there weren't any other green elements in the room it might clank. I'm thinking the other bathrooms I did had low iron glass because there was no green tint, although that was ten years ago and I can't remember having a conversation with the fabricator about it. Ask your fabricator if they can show you samples of each type. If it costs twice as much you will have to decide if it is worth it to you and I would have to see it in order to make the choice. At least you're able to decide - in the bathroom I just finished the fabricator didn't even bring it up, maybe because of the high cost differential.

I have regular glass and really don't notice a noticeable tinge. When I was remodeling I did read about it but decided it was not something I was going to get.

FWIW I actually paid a sigificant amount in order to have Showegard glass installed in my shower because having to squeegee a shower every time it was used was a non-starter for me. I have been using my Showergard shower for about 3 1/2 years and it looks as good as new. I hose the glass down to get rid of any errant splotches of conditioner or shampoo but otherwise do nothing except once a week when the bathroom is cleaned by my cleaning woman.

I am pleased with my decisions - getting Showergard and not bothering to get low iron glass.

We have white tile in a shower and paid significantly more for low iron glass. I am so glad we did as the end result is worth every penny.

"I thought glass was glass..."

Optical lens design relies on there being hundreds of different types of glass. But more relevant to showers is the requirement for the glass to be of a particular type that is tempered so that it shatters into small pieces rather than sharp shards.

I suggest it with white tile but otherwise it’s not really needed imho. We all have things we notice though so may not be able to unsee the green hue now that it’s pointed out!

I have used low to no iron glass
 The only place I use this is over an expensive oriental in living room office etc. It is not worth the cost for a shower However there is a glass that you never have to clean for a shower
 That is a good investment. Ask your supplier.

What @HALLETT & Co. said!! In my experience, it’s maybe 20-30% more. Definitely get the coating.