The proprietary argument against Sony always annoys me.
What do "Betamax, MemorySticks, RootKits on CDs, UMDs, MiniDisc" have to do with the Alpha line of cameras? The only thing that's proprietary is the Lens mount (just just like everyone else) and the flash mount. It's not like you can interchange Canon and Nikon flashes. Well, you could put a SB-900 on a 5D Mark II but why would you want to? You'll lose most of the function. You could fire is manually but you can do the same on a Sony camera with a $15 adapter. For OCF it's even easier. As for Radio TTL controlers for the Sony only being out for a year, how long have they been out for Canon or Nikon? For that matter how about Pentax?
Sony have plenty of failing when comes to the pro level but come on let the betamax thing go already.
How long have pocketwizards or radiopoppers been out? A lot longer than it's been for anyone making a Sony Compatible TTL flash system.
And yes, actually you can use Nikon and Canon flashes wirelessly off camera together. However, the one brand excluded from the list of supported flashes was... Sony. THE ONLY brand excluded was Sony. Strange, huh? The thing is, with Nikon and Canon flashes being fired off camera manually, I don't need to buy a $15 adapter for every flash I have. That's my point. The accessibility isn't there for the Sony system IMO. It doesn't appeal to more than photo enthusiasts, or hobbyists. That's why I ditched them and got something more versatile.
Even with the update to the triggers (Cactus V4's to Cactus V5's) I was using, they STILL don't support Sony, and they were introduced last year. Heck, I can't even find Cowboy Studio triggers that work with Sony natively. The "proprietary" argument may not be so irrelevant as you think.
When you say say you can use Canon and Nikon flashes together, I assume you mean manually not with TTL. If they can work together in TTL, I will cede that is impressive. As far as radio triggers I use Cowboy studio triggers and receivers I can mix and match sony, canon and nikon flashes with out adapters. Sony/Minolta mount on the transmitter and iso or S/M mount on the receivers as needed. I would agree it would be nice if Sony went to a iso mount but I haven't found it to be a major hindrance and only a minor benefit.
I would agree if a photographer can justify purchasing a group of high end Canon or Nikon flashes with matching PW or RP wireless transceivers by all means they should.
I agree that in most ways the Canikon systems but better and more full featured than the Sony system. The problem as I see it, is Sony not developing pro level features in favor of amateur features. Not proprietary standards, and certainly not because of betamax almost 40 years ago.
Anyway, I would prefer not have this thread turn Argiesque. I think we can agree Canikons are better systems than Sony. I just think the proprietary standard of the flash mount is not as much of an issue as you.