If it's your only knife, and it's for wilderness type of carry, I'd go with the Rat7. It can do some modest chopping. Just yesterday I pounded it through a 3 inch cherry branch, all the way through. No problem, took about 5 to 7 good whacks. The extra inches give you a little more spine and a little more front weight.
If you already have a larger chopper for the bigger tasks, then the Rat5 should be fine. If this is your one single wilderness knife, get the Rat7.
If it's EDC, I'd look for something else as both are going to appear a bit hefty for walking through the local shopping Mall.
I really don't believe you will be hiding the Rat 5 from sight, they are pretty much going to look the same in their sheaths, while on your side.