We were in the same situation 3 weeks ago. We went with 2.6.9 while the nits were being sorted out in 2.7. I am glad we did. We launched on Thursday and immediately began selling registrations.
I love 2.6.9 but cannot wait to upgrade to 2.7.1 once I am convinced there are no remaining 'nits' that would affect our client adversely.
I have to say, 2.7.1 feels pretty good. It seems like once I got things rolling, it works pretty smoothly. A couple of things that I would have liked to see, but it seems like I'll be able to customize it enough to make it all work out okay.