Been using mine for the past couple of days. Besides the initial firmware update, there was another update yesterday. For any disappointed upon first use, give the software some time to be refined now that the hardware is out in the wild and Valve is getting a ton of user metrics and bug reports.
I'm a PC couch gamer and love the flexibility of steam input and the trackpads, so this was always going to be a fit for me. I'm waiting for them to figure out mouse trackpad use in Windows, as it is a worse experience than the original steam controller out of the box. Quirks like you have to have Steam open and not minimized for it to work (or at least not minimized from big picture). They will get there.
One surprisingly great thing about this controller for me is the d-pad. I usually only play 2-D platformers on my Steam Deck (and before that my Vita) due to the placement and comfort of the d-pad. This is the first controller where I'm not disappointed at the d-pad at all when playing a game like Spelunky. It is weird, I got this $99 controller for the trackpads and premium features, yet I'm drawn to playing games with a d-pad and button inputs.