I'm looking to upgrade from my built-in flash on my XS. I don't have a lot of need for it, but it would be nice. Primarily for some fill work, maybe a little gym sports in the future. In other words, I don't want to spend an arm and a leg. I've been bidding on some used 420EX flashes in the $120-$140 range. Basically I'd like to not go any higher than this. I was looking into other brands, and I see a couple that have caught my eye and I was wondering if anyone had any thoughts on these: Vivitar DF340Z - $65 Sunpak PZ4000 -$109 What can the 420 do that these can't (other than wear a Canon badge). I realize that you get what you pay for, but like I said, I don't need a lot here. Is there a cheap gem I'm missing out there? Thanks in advance.