I use IAR's 8051 compiler, and have found excellent support from them, if I keep my support agreement up to date.

When I had to work on an AVR project, I decided to give CodeVision a try, because of the huge difference in cost (it's $180). I didn't want to use Imagecraft C, because they did not support bit variables, which would have made porting some of my 8051 code more of a pain. (Imagecraft may have changed since then, it's been a few years...)

CodeVision has offered excellent support, direct from the compiler writer himself. Email support is about 24 hour turn-around, since Pavel Haiduc is in Romania (I'm west coast US, a good time difference for me). There is also a CodeVision group on Yahoo, which is active and is closely watched by Pavel who frequently responds.

CodeVision has a code wizard that will help set up the hardware, which is nice if you're new to the parts. I've found that I like to do things my way, so I rarely use it.

CodeVision uses Atmel's AVR Studio for debugging. You can either use Studio's simulator or the JTAGICE MkII. Both the regular JTAG debug and Atmel's On-Chip Debug are available on most of the newer AVRs.

At this time, CodeVision does not have a command line compiler. It also compiles and links everything each time, making compile time slower than IAR. It does make opimizing work a little better. The command line compiler and module-by-module compile are frequent requests and Pavel is working on it for the next major upgrade I believe. He does minor upgrades/bug fixes often, every month or two, often with a beta version available for downloading to get somebody running quickly.

This rapid response to bug fixes and enhancement requests really puts IAR to shame by comparison.

Dennis