I signed up (for free) and played around on my laptop....the built in mic on my laptop not only recorded my voice, but was also picking up the internal noise of the drive which was quite annoying. I tried it on my desktop and plugged in my guitar (through my Toneport DI) and the signal was quite good (no humming noises etc..). It recorded my guitar quite well and I messed around with some of the presets and vaious styles.....some fit in well while others didn't.

After recording my track with Ujam, it does map out the chords (although not quite correctly, but fairly close) which you can very easily edit and match it to whatever chords/vocals you play/sing to. A cool feature is once you sing and record a track, you can choose it to be an instrument and it instantly changes it to which ever instrument you select. You can also easily edit each note for that imperfect take or if it doesn't correctly convert to the right notes. There's a lot more features I didn't get into like where you can edit the type of instrumentation so the it fits better into the style you're playing (editing the kick drum, types of bass, piano etc...). 

Basically, it has plenty of options in pre-defined styles and fx for "anyone" to quicky jot down an idea and instantly put it into a song, but is only limited the available choices.  I only played with it for a few hours and afterwards was longing to fire up Sonar and build a song from scratch. Personally, I get a lot of satisfaction from playing all the instruments in my songs (even with my limited abilities) and found Ujam to be counter-productive to what I want to do seriously. For just messing around with something quick, easy, and since I love almost anything that's musical.....Ujam will be there on my desktop for those uninspiring or boring days (I'd probably still go to my DAW...).  As long as it's free, it'll reside on my PC.....