Marcus Ian , Nov 28, 2012; 11:17 a.m.
2. Yes. (many of us have)
3. Yes, both. They are designed to do so, by focusing the light specifically, it uses less power to give the same exposure.
4. Camera - ETTL is ETTL.
2. Same answer.
5. The major differences are that the 430ex has lower max power than the 580/580II, and that the 430ex can ONLY act as a slave when used in a wireless setup. The 580s can both act as masters. The 580II has a metal foot a shroud, and is designed to be a smidge more efficient and powerful than the 580.
6. In your shoes, either a 430, a 580(1) or a 580II will work fine for just about everything you'll consider doing. In your shoes, It's probably not worth it to get a 580II, I'd stick w/ a 430, a 550, a 430II, or 580. All of those will do what you need, and work well doing it.