Any experience with the MXR Micro amp?

I'm always in the habbit of trying out new overdrive and dirt pedals, and a MXR Micro Amp has come up on the local Craigslist. Is it worth trying one out? What is a good price for one? And one other thing, on my Line 6 M13, it says that the "boost comp" setting is based on the Micro Amp. Will the Micro Amp add any compression to my sound?