My feelings on these things is people are often happy with them at the price but that doesn't mean they are great/as good as the official flashes. Also 3rd party flashes will often be bought by people who have never owned first party so they have no way to form a comparison.
For amateur use then they seem ideal but I just think I understand why people pay the prices for the Canon./Nikon models. You might get 90% of the Branded item for 20% of the price but if it starts malfunctioning in a paid event then it is a bit more of an issue.
I was going to get a few of them instead of fixing my Canon (£135 each), but after the trouble I had with them, I think the Canon is worth every penny for my purpose.
I can't have flashes not firing...good thing I still had 3 working Canon ones (one was melted on the outside but still worked!) so still managed to have 2 off camera flash.
So do the Canon ones cycle quick enough to keep up with the FPS of a 5d3?
So I've decided to agree with you guys - The Yongnuos are going back - Did a test on the bench and after a few shots, it changed every flash group from ETTL to Manual for no reason what so ever, then lost sync. Also it couldn't keep up with burst photos at all. On burst it fired once every four shots and that was with three flashes firing so it didn't need full power by any means.
Going to stick with my old Yongnuo's (2 x 565EX with 622c and 622c-tx) ironically and just save up for the proper Canon 600EX's when the time comes to need them. However next upgrades are definitely a tripod and then a 24-70mm F2.8 and Full Frame! I never really wanted to shoot with flashes but with a 700d indoors, all I get is noise!