I was able to buy one of the new Steam Controllers and it arrived yesterday. Initial impressions are it's pretty good. It's not as bug or cumbersome as it looks, the part with the track pads isn't as wide as the grips so your hands go underneath them.

It has two buttons underneath you can program for games and the trackpads offer a bit more versatility as well. They default to mimicking the sticks so you can use either or reprogram them completely, which I'll have to look into.

I have the original and I like that one, but without a second stick I felt like I had to adjust the settings for each game. I wanted it to act like a mouse in the middle and a joystick around the edges, so I never used it as much as I should have. The triggers on the original have more travel and a noticeable click when pulled in all the way, so you could get really deep with programming just that.

It's a good bit of hardware, but expensive. For half the price you can get an 8bitdo Pro 3 off Aliexpress which has a similar amount of macro buttons and is a little bit more flexible with what it works with. The new Steam Controller can just be further justification for me to build by own Steam Machine further down the line