I am planning on getting Parallels set up but am unsure if there is a big performance hit when running Windows from the Bootcamp partition vs. just running it through Parallels normally.
Does anyone have experience doing so and thoughts?
While running under Parallels both will have a similar performance.
The only difference is that the bootcamp one can be booted natively (and have better performance when booting natively).
No need to migrate. You can use the Bootcamp partition in a virtual machine and switch from virtualized to native Windows and back if you need lots of (especially graphic card) power.