I’d say use case scenario would make the most difference of what kind of camera to get. Are you using it just around the studio, or more as you mention out and about for research?
Personally, I find portability to be the most important after a certain level of quality. The best camera you have will be the one you have with you.
I have a small point and shoot Samsung NV10 that gets a lot of use. Good for macro and small details. Video isn’t the best but the camera is 5 years old and the newer ones all do HD.
I bought a Samsung micro- 4/3 NX200and it’s a great camera, but it doesn’t get much use as I need to lug it around. Even when I do use it, it’s mostly on the Auto mode, so all the fancy adjustments don’t get used. I’m considering getting a pancake lens on it, which should help the portability and also the lack of decent macro.
I still tend to use the iPhone more than anything as it’s just easy and the pics are pretty good out and about to document things and the macro is very good.
I use my camera mostly around the studio to take pics to put together product review comments for suppliers and out of the studio for research.
For beauty shots of catalog quality you’ll need more than a good camera. A full lighting set-up, background, power pack, etc. I hire a pro when it comes to catalog product photography though I have considered getting a "studio in a box (a few lights and soft box) for quickie needs when I just need a few temp shots not at full quality.
I think in most cases a DSLR is overkill. I find it hilarious when I see tourists on the street lugging around a big DSLR. Most people don’t use all the manual functions, and these days you get more than enough MPs from a point and shoot for most uses unless you are blowing up to billboard size. A Micro 4/3 at the least is a good compromise as can shoot RAW and can get 20+ MPs.
R