I was really interested in the Icon M range when they were first released, due to the form factor and the modular design if you wanted to start small and then expand. But there appeared to be several problems with the build quality as skijumptoes mentioned, with units arriving warped and so not sitting flat, noisy faders etc (see this rather extensive thread over on GS: https://www.gearslutz.com/board/product-alerts-older-than-2-months/1109985-icon-pro-audio-platform-m-now-shipping-6.html), the lack of Mac software at the time and good tech support.
In the end I went for the X-Touch after using an X32 for live work. I know they're quite different beasts, but the build quality of the X32 is pretty good considering . The X-Touch appears to essentially be a Mackie clone (runs on the MCU protocol) and I'm really impressed with the integration with Logic. It's a solid unit, the faders are pretty quiet especially on quick moves (YMMV) and the jog wheel is precise, at least for how I use it.
Downsides - it's a bit chunky, so much so that I've had to cut a hole in my work surface and sink it in to make it more comfortable to use. This, I guess, is down to user preference. The V-Pots are a bit more wobbly than I'd like and the scribble strips seem to have a sweet spot for viewing angle, even once you have adjusted the contrast. Finally, the LED channel meters are not really quick enough to give meaningful visual feedback, but other than that I'm impressed by it for the short amount of time I've been using it.