SD+ Users - If you were me...

I recently purchased 5.5, and have installed it. I'm about to go live with it, but am facing a dilemma that I hope you seasoned SD+ owners/users will give me some advice on.

I can either go production with my 5.5 environment, or I can wait and install 6.0. We'd really like to use some of the new features of v6, most importantly MS SQL support.

So, should I go with a more stable 5.5 and risk a messy upgrade and conversion to v6 w/ MS SQL, or should I wait to install on v6 w/ MS SQL, but contend with a new, possibly buggy version?

What would you do if you were in my shoes, having experience with SD+ upgrades in the past?

Thanks,
Christian