It seems you have 2 questions here, I'd suggest asking them in 2 different tickets.

Regarding QuickBooks (QB): I doubt very much that any migration script exist betweeen QB and OpenERP. First, QB being proprietary, I'm not sure it allows to plug into its db. I assume you have to export first. Second, you need to specify what exactly you use in QB, what version of QB you use... In brief, it's a migration project in itself, and needs analysis. Regardless of the chosen ERP, and unless you actually use a very little part of QB, don't expect such a migration to be cheap and fast.

Regarding Microsft Dynamics SL : It's a vast subject, but let's start with: what functional area do you want to compare? Regarding total cost of ownership (TCO), implementation and so forth, no idea, but the main difference is that you're on an opensource platform with OpenERP, where you are in control of code, processes and data, opposed to a proprietary system where you're 100% captive of Microsoft. The average lifespan of an ERP being 10 years, make your own choice ;-)