I have the Ultimate Sweater Machine. I've used it only a few times in the um.. 5 years or so I've had it, and only when it was brand new.
Don't get me wrong, I think it's a great machine. But I'm not all too excited about machine knitting. I LIKE hand knitting, so I just prefer to hand knit. I keep the machine because it was a gift from my Dad, and in the event I ever want to produce some stockingette very quickly.. I dunno.. I could knit a blanket in a day or two as a quick knitted gift.
But I much, much, much prefer hand knitting. If you think you might enjoy machine knitting, by all means, buy it. It IS fun, if nothing else. But it's very, very different than hand knitting... not even in the same category as far as I'm concerned.