I use my MacBook Pro for iPhone development and am considering using it for Android as well....
Has anyone seen any issues with developing for Android on a mac?
I have had no problems using a Mac for Android development.
I have Eclipse and Android stored on my work Dell laptop and it seems to be working ok.
I have a DELL desktop PC at work. They work just fine too.
Anyone know what type of machine the Google engineers used to develop Android on?
Though this can be answered by those who actually work there; in most of the official Android tutorial videos on the internet, I have seen MAC more often than a PC.
If you are looking to download Android source code and compile the SDK tools or OS, MAC is the way to go. You wont be able to do that (easily) on a PC.