I am going to convert an AVR (ATmega128) project in C produced by an outside vendor to a '51 for product line standardization. I have had bad experiences converting non-functional code to another processor, so I would like to make the thing work with the AVR before converting it. Does anyone have positive experiences with a full AVR compiler costing less than the IAR, I hate to pay $2400 for something I'm only going to use for a month or so. Also a "very different/very similar to Keil" statement would be appreciated.

Sorry for the "thin" relation to the '51.

Erik