... (I mainly shoot in bars and small clubs so no tripod)
1080 would be fine, but for the same money I'm thinking it may be worth going with 4k. Especially if it means I can record at 4k, render at 1080 and zoom pan / crop where required, and not lose any quality.
Any thoughts? Thanks!
My thoughts include the idea that there's really no free lunch. If it costs the same, you will loose quality. Have to. The smaller pixels points to more noise in low light. The 4x processing required of each frame points toward lower frame rates for the same money. The 4k image with the same size sensor(s) puts a premium on lens quality. Etc. I'm just saying that for the same money, you're almost required to get less image quality.
My other thoughts include the idea that if you're hand holding, just like with a stills camera, you aren't putting a premium on sharpness. So, why the interest in 4k?
The sole advantage I can see is the ability to pan/tilt and crop in post (if your output is going to be HD or lower of course). But, that's a PITA to do if you have to do it all the time. I'm a fan of trying to capture correctly as much as possible to minimize post processing.
You didn't ask for advice, so feel free to reject mine out of hand -- but my advice is to go for a better HD camera, maybe one that can give you higher frame rates (that you can use for slow motion, because everyone looks better in slow motion), or better/faster glass, or better/faster in camera image stabilization, and of course better low light capabilities. The HD cameras are darn good now, while the 4k cameras are all in their infancy still.
EDIT: Oh yes, how could I forget? Get one that that has XLR inputs. If you're going to be recording in a bar, you're going to be recording in a den of RF devices. Even if your camera only gets a scratch track so you can sync to a recorder in post, it helps if the scratch track is listenable. Just sayin'.