Radiopopper PX and the new Pocketwizard Flex & Mini units are the only ones that work with ETTL. When it comes to manual triggering, Cybersyncs are the best buy for the money, in my opinion. I've owned a couple of ebay triggering devices (Cactus V2s, CTR-301), but Cybersyncs are substantially cheaper than Pocketwizards, yet are just as reliable. They work up to (and maybe a little farther than) a football field away. Pocketwizards will give you more range, but they cost substantially more. I don't need more than the 300ft range of Cybersyncs, and most likely never will. I've been completely happy with the set I purchased in April. In fact, soon enough I'll purchase another receiver and another trigger as backup.