I am a pro, I write for automotive magazines, mostly shooting tech- lots of welding, greasy parts, dirty, nasty environments. Up until now, I have been using rebel-series cameras because of that. I don't shoot a lot of features, but I do so every once in a while. I also shoot drag racing and road racing couple times a year. I have several crop lenses, only 2 EF lenses (nifty fifty and a cheap 70-300 which I never use). My main lenses are a tamron 17-270 and the kit lens for the T1i which I mostly use in the shop when things are nasty.
I also do a lot of video. I am currently using a canon HFM41 for my tech videos. It does quite well in the studio and in the field. It doesn't look as "professional" as a higher end vid cam, but it works and I get good results.
I am wanting to upgrade. I hate flashing under a car, it looks horrible and flash burn is inevitable. I can always add light, but they get in the way when you are working on the vehicle and what works for one shot does not always work for the next. I typically shoot my T1i at 800-1600 in the shop.
I have looked at the 7D, I really like it, it works with crop lenses, has really fast FPS which I like for racing BUT then I saw the 6D two weeks ago. I love the full frame, the extremely high ISO capability, WiFi, GPS, all that stuff. It shoots good video, has the mic jack (the T1i does not have a mic jack, which is why I don't use it for video much, I use wireless lav mics), all the good stuff at a great price. The biggest issues are this- slower FPS, which I only need occassionally, I have to buy EF lenses (I need some L glass, but it's expensive to do it all at once), and it's not a 5DMIII.
Tonight I was reading a thread that mentioned the refurb 5DmIIIs, while the price is up from when it was posted, I can still swing it, but then I have less for L glass.
I don't know what to do. I know the 7D will be a huge jump in quality, but so will the 6d and the 5DmIII even moreso. If I buy a 7D, I will likely regret not going full frame when I had the money. I can't afford a new 5DMiii, so refurb would be my only option. I have had 4 rebels and they have served me very well. I put 76k on my XTi and it is still working. My 11 year old won a blue ribbon at the fair shooting my 10D when he was 9. I really want to upgrade, but I need some help making the decision. The 6D fills the void between the 7d and 5dM3, but I still have to get all new glass. My son will get the T3i, so no point in selling it. I'm also nervous bringing 3k worth of gear under a car or in front of a welder. Ever camera body (and even a few lens filters) I have has tiny little slag burns on them. It's a tough choice for me. I live off my cameras, but spending 3-4k on new gear is tough. Thoughts?