I used the shredded cypress in the past, it breaks down fast and doesn's last long. The most long-lasting mulch I used is pine bark nuggets (at least 2 years). My neighbors use bright red colored hardwood but they have to re-apply every year. None of these work as well as leaves to retain moisture.

My village has a free mountain of bark mulch within walking distance (from trimming trees). Electrical companies like ComEd usually have a big pile of mulch (from trimming trees). I find the free horse manure to be better in suppressing weeds. It has lime, quite alkaline, and the weeds hate it. If your soil is acidic, it's good stuff. If your soil is alkaline like mine, use only a thin layer once a year on top of bark mulch.

I have Cypress mulch that has been down for going on 4 years now and it is still holding good. There is also come Cedar mulch as well as wood chips that a tree trimming service dropped off several years ago that are still doing the job. A 2 inch thick layer is about the minimum for "weed" suppression and I most often put down 4 inches, sometimes more.
A mulch should recede into the background and not detract from the planting as many of the dyed mulches do. Some of the dyed mulches are made from scrap lumber and can contain OSD and plywood as well as pressure treated timber. Dyed mulches are not something I would use.

I can't use any nugget type of mulch because of slopes and rainwater runoff. Large surface area and light weight lead to mulch getting carried off to my neighbor's yard. Finely shredded seems to do reasonably well.

Around here cedar mulch is 40% more expensive than hardwood mulch. But if hardwood lasts just 1 year and cedar can last at least 2 years it is probably worth the higher price to get cedar. Since we do all of our own gardening it is less work to get cedar.

I started with some free mulch in big pieces, but I changed to like a microbark, because I can use it in my compost bins when I am done with it. The big pieces were a pain, since they don't decompose. Weeds pop up more with big pieces. If you go "big pieces" you need it to be even thicker. Anywhere light can hit the ground you will get a weed coming up. This way, although I had to pay for it, I get something back from it when I have to replace it.

I don't know what is used to dye mulches but I've been interested in learning. It has to be incredibly cheap for it to be economical for them to use. For example, red might just be iron oxide, completely harmless. Black, maybe that other type of iron oxide. But that's complete guesswork.

My main objection to the stuff is the fake appearance where I'm trying to be natural, so I haven't got as far as whether it's harmful to the soil or plants.

ikea_gw - do you really find leaves ugly? I'd take them over coloured mulch any day. And if you don't mulch with them you'll need somewhere else to put them.

I like the look of shredded leaf mulch. In fact, I would suspect that from a distance shredded leaves don't look any different from shredded bark. But of course, everyone has a personal preference.

I had gotten some mulch made out of shredded pallets and it lasted a long time - 3 or 4 years...

You can always put down a couple inches of shredded leaves to feed the soil, and top with whatever kind of mulch you want to look at. Best of both worlds, and it gives you a nice thick mulch at half the cost since the leaves are free.

We have mostly oak trees and tulip poplar trees. Even if I shred them with my leaf vac or lawn mower they remain a blonde shade of brown. Not really my cup of tea for more formal front beds. I use them in the backyard since it has a more naturalist look and it is so thickly planted once spring comes I can't see the mulch anymore.

BUT... our county collects leaves in the fall and they offer shredded leaves mulch for free. I am guessing they are right in the middle of decomposing because of the smell and heat but they are black. I went to the leaf deposit site with an armful of garbage bags and got enough mulch for the front beds. I don't think they will last more than a year but since they are free I am ok with having to redo it annually.

Question: how deep should shredded leaves be for weed suppression? 2 inches, 3 inches?

I would guess at least 2-3". Depends on your weeds!

I try to do more than 3", if I have enough material. Keep in mind as you are placing the mulch, it will compress/shrink down after a few rainfalls so be generous.

BTW...Great find on the free mulch from the county!

I think 3 or more inches is best.
More then 5 inches can be blown around by the wind.
I always spray fresh mulch with water after placement to settle it in the bed.
If you want the leaves to start rotting to feed the soil, put down 1 inch layer, then add an organic fertilizer or finish compost & put 3 more inches on top of that.
This has worked good for my garden in the past. I mostly put down finished compost on the first layer of leaves, then put 2-3 inches of mulch on top.

I would use a deep layer of the free shredded leaves - 4" or more - and then top it off with whatever you find more aesthetically pleasing. That way you get the benefit of the nutrition of the leaves, the weed suppression of a deep layer, and the cosmetics and wind resistance of a wood-based mulch.

I also do something similar,compost,then leaf mulch, hardwood mulch and then a top layer of pine straw for the Southern look.

Many garden writers have said that mulches should not be thicker than 2 inches even though, as I have found, that depth is barely enough to suppress "weed" growth (unless something is under that mulch), conserve soil moisture, aid in controlling soil temperature, although that will add organic matte to the soil.
The mulches I put down are 4 to 6 inches thick even when I use newspaper.