I like my 50D. I'm not in love with it though. It's a fine camera, but I find some things about it to be less than perfect in my eyes, so I'm looking to upgrade within the next few months to a year. Budget at this point is unknown, but I expect all three of the bodies listed in the title to be within the budget.
What I like least about the 50D is the noise at anything over 800 ISO, and I'm really not even happy at 640 or 400. IMHO, those speeds should be essentially noise-free with a camera of this era.
I'm also not super-fond of only 9 AF points.
AF speed I'm borderline on. I'm ok with it, but have nothing better to compare it to.
I'm ok with just about everything else with the 50D, and really the most disappointing aspect of it is the high ISO performance. I don't have really fast glass for the most part, and find I'm bumping the ISO up to uncomfortable levels to maintain desired shutter speeds, sacrificing IQ in return. 
Of the 3 above, I know that most are going to really steer me towards the 6D. From what I've seen, the high ISO performance is awesome, and pretty close to the performance of the 5DIII (definitely out of the budget). But, it's somewhat of a lateral move in AF points, but a huge step up in overall IQ being FF. I also really don't want to have to change my WA lenses (17-50 & 10-20) along with a body change.
The 7D gives me the AF speed and points, but I don't really see it as much of an improvement in high ISO performance. Yes, it's better, but everything I see/read says not by leaps and bounds. I really would like very usable ISO 3200 and above.
The 7DII looks like it's going to be released here soon, and I'm hoping it addresses the noise 'issue' of the 7D. And yes, I no noise can be handled in PP, but I'm one of those that feels any additional PP to correct native deficiencies of a body or lens should be proportionate to the cost/reputation of the equipment. It's why I hardly ever use my 85mm (CA).
The 70D I really hadn't considered, but in some reading, looks like it could also be a contender for what I'd like, but I'm not sure.
I guess if I had my choice I would want a 7D with 6D noise handling. I want an upgrade that will knock my socks off. So what's going to expose my bare little piggies?


