I got the atlas stamp I2C code working.
I'd say using serial is better than I2C.
with serial, you get a dedicated connection. You can send a series of commands in one send and you can pause and resume sending/receiving if needed.
with I2C, you share the bus with other I2C devices. You have to send one command at a time, and must read the response. If after you send the command, and the response code is pending (read the response too soon), you must resend the command again. Unlike serial, if it is pending, then you can come back later and read again without resending the command.
I have to rewire my test setup so I can est running 2 stamps, one serial and one i2c to make sure everything works together. I think this should be ready sometime next week.