which body?

Hi, I have a Canon 100m 2.8 (non L) on the way. I'll try it on my 7D and 5Dm2, but wondering in there is any consensus on which usually performs better, a crop or full frame sensor.

Until I add some kind of bracket I'm going to use a 580EX on camera with a Lumiquest mini softbox.

The 7D's crop sensor is arguably the better for photographing small insects as they will fill more of the frame. The 5DMkII is arguably the better for photographing large insects, frogs and such, as they will remain inside the confines of the frame and/or give you more composition options.

The performance and quality will be similar I would guess... apart from noise, the 7D images might appear to be noisier... you may notice more light from the 5D making it easier on your eye but at 1:1 I would guess the difference would be slight. If you add extension tubes, etc for higher magnification the difference will become more pronounced.