I ordered my first set from QVC and all future dvds I've gotten from ebay. QVC was fast and everything went very smoothly.
As for coordination, it can be a tiny bit tricky at times. There are occasions where I stumble over my own feet, but it's usually when I'm trying too hard. When you just jam to the music, the moves flow really well. There are also a lot of ways to modify it to make it fit your coordination level (ie lower kicks, not turning quite as far into punches).
Finally, turbosculpt. I don't actually do this workout too often. It is a fantastic burn, but I am horrible at lunges and the horse stance. They end up hurting the muscle right at the top of my knee, which I know means I'm doing them incorrectly, but I can't seem to figure out how to do them the "right" way. I normally skip that video and do the booty sculpt, lower body jam, or the 3T. Most of these have the horse stance or lunges, but it seems like the time spent on them is less so I have more fun and I am more comfortable. As for how often, I normally try to make 2 days out of my 4 or 5 workout days toning days, and never 2 days in a row. The alternating gives my muscles a chance to relax and it makes sure I get cardio in as well. Once in a while I'll be really motivated and do a cardio and a strength, but those are rare (I often question my sanity on those days!)

