Standalone proects

I've just ordered a pile of Attiny85's (they're really cheap!) to make permanent versions of a few of my arduino projects,
but while I'm waiting:

what are the main limitations of an Attiny85 over a Arduino Uno ?

  • lower memory and less I/O ports
  • port numbers differently

but will all the same code generally work with a recompile ?

e.g the easy servo drivers, i2c stuff for wii acceleromters etc ?

AIUI I'll have to configure them to 8Mhz, use arduino as an ISP, and download a few files for the IDE, but am I missing anything else ?