I have a Micro as well and while I loved the Mini Gameboy idea, I think its a shoddy product. I bought it when it first came out, about 6 months later the top right shoulder button just stopped working for no reason. I keep it well taken care of, like not dropping it and keeping it away from dirt and dust. But that button refused to work. Luckily my warranty was still in effect(the last day) so I returned it got it exchanged. Was working pretty fine but a year after the SAME THING HAPPENED!!
My warranty is expired now but how can it have the same problem? Obviously a shoddy product. Dissapointed... 
I'm sad to say that I've had some problems with the left shoulder button on my first Micro after a year of heavy play and sitting every day in my jeans pocket. You have to press it in a certain way to make it register, if that makes sense.
It must be a flaw in the design. What's really crazy is that the shoulder buttons were one the main criticisms of the Micro when it debuted.
I still don't think it's shoddy, though. The screen is really far superior to the SP screen even when they're both well-lit. Also, having a game system (basically an SNES) be roughly the size of an NES controller is just amazing, IMO.