Liquid was always my favorite ROM on ICS, so you can only imagine my excitement when I saw this had been posted.
I've been running it for ~7 hours now, and I can't discuss battery life because it's been plugged in most of that time, but it's definitely at least as smooth as Jelly Belly (which is what I was running earlier) and the customization options are coming along.
As far as it being an alpha version, one of the devs, hiemanshu, had this to say:
So far no bugs with the actual core at all! Its only called an alpha because we are still adding features from 1.5MR1, I have been using this for a while now, and no known bugs so far.
I have noticed (and reported) a couple bugs though:
-If you set custom lockscreen shortcuts the first time, the camera shortcut breaks and you have to set it yourself again manually.
-If you change the AM/PM style for the clock, you can't change it back without changing the clock to 24-hour mode and back
-Google Voice Search doesn't work until you download the appropriate language pack from Google Now->Settings->Voice->Download offline speech recognition
That's all I've found, and they're all very, very minor. Overall the ROM is super fast and super stable, and I've always been a huge Trinity kernel fan so no complaints there either.
tl;dr: Team Liquid's done it again
Edit: btw, bcote, are you going to keep the OP up-to-date? Or should I or someone else start an official unofficial thread? haha.