Like the Usotsuki said, BASIC programs will run at whichever CPU speed you set, fast or slow. The setting affects the Apple II layer as a whole, not just machine-languae programs.
What are my other options for BASIC? Are any of the options mostly Microsoft compatible?
Applesoft BASIC is very similar to Microsoft BASIC, and in fact that's where the "soft" in the name comes from. Most if not all of the differences come from the extensions added to Applesoft for things like graphics and character positioning, so odds are a program written purely in Microsoft BASIC will work fine on the Apple.
There is also Integer BASIC, which was the standard BASIC on the original Apple II, and can be loaded into any Apple II afterward, IIGS included. Integer BASIC is very limited compared to Applesoft BASIC and so there isn't much reason to tinker with it, but sometimes you'll find a really old program from the II/II+ era written in Integer, so it's good to have around just in case.