It will not be the same performance-wise as a dual boot but it won't be terrible. You should look at the memory though.
Giving a Windows VM only 2GB of RAM will probably be what makes a noticeable performance hit that you will see. If you can give it 4GB or so when you are actively using Visual Studio, your dev experience will be much better. This is especially true since you mentioned running Visual Studio and SQL in the VM.
I actually do this on OS X all the time. I have 16GB of RAM, though, so I can give the VM a lot.