Just went through the exact same thing. I was using Epson Exhibition Canvas and loved it, but the price was a factor, although defects were the bigger problem. The defects I had were runs in the coating and of course the seeds.
I ordered a roll of both the Everyday Matte and also Simply Elegant Matte Canvas. The Everyday is 100% poly, so I figured with no cotton, there wouldn't be seeds. The surface is absolutely perfect, almost too perfect in that there is no randomness. The only issue is that it is quite thin/light. Once stretched, nobody could tell, but if you deliver the canvas to a customer as a roll, it won't have the same weight/sturdiness. It also doesn't seem to have the stretch factor that the Epson canvas has, but it still stretched fine. On the plus side, the everyday canvas is thin so the corners can be neat. There was zero flaking once coated, and the corners were perfect in terms of no cracking. Other than the weight, I love it. It comes in a 75 foot roll, so you're not stuck with a few feet on every roll that you can't use, which is common on the 40 foot rolls, the price is therefore much cheaper per foot, and the lack of defects makes it a winner.
The heavier canvas, the Simply Elegant Matte, this compares well to the Epson. Its a little softer, but still has the thickness and weight. I think it has less imperfections, but this might perhaps vary with the rolls given that it too is a cotton/poly blend. It comes in at maybe 20% or so cheaper and there is hardly any difference between the more expensive Epson. So really.. there is no point in sticking with Epson for canvas. I haven't seen any runs in the coating yet, but I'm only on my first roll.
If they made the everyday canvas thicker/heavier, but still 100% poly, this might be quite the product. One drawback is I think being able to shrink the cotton canvas once stretched with a bit of water in the back to take up saginess or work out a dent, which you cannot do I think with the 100% poly canvas since the polyester fibers won't shrink I imagine (haven't had to try yet though). But if I am throwing away less canvas, this is the biggest factor. When printing on canvas, there is simply too much wasted because of defects and its too expensive to waste, unlike paper which is quite a bit cheaper.