I just added a 580EX II and a ST-E2 transmitter to my equipment. Previously I only had a 420EX speedlite, so naturally I am happier. I love being able to throw both speedlites on tripods and move them around the room.
I question though how amateur is this setup and what limitations will I soon find? Any help or comment is appreciated.
The setup is as amateur or pro as the user. I use a less sophisticated setup (wireless triggers and manual flashes, no TTL) at weddings and on location portrait shoots. It'll serve your needs for sure.
If you haven't already, checkout //www.strobist.com Lots of great info there on using portable lighting... and he's no amateur either :-)
The AA's are fine, not sure how long the 2CR5 lithium battery in the ST-E2 will last though. The manual says about 1500 transmissions. There seems to be a wide price range on the battery. Anywhere from $8 to $25. Have to wonder if the $25 battery would actually last 3 times longer?
The problem is I have nothing else to compare. I can tell you I absolutely enjoy being able to place my speedlites anywhere I like. As for ease of use and reliability I have had no issues yet.