Firefox	IE	Opera	Safari
Windows	No known issues	No known issues	No known issues	N/A
Mac (PowerPC)	No known issues	N/A	No known issues	No known issues
Mac (Intel)	No known issues	N/A	No known issues	See Note 1

Note 1: Some Intel-based Macs running Safari crash when displaying the maps due to what appears to be a bug in the way Safari handles AJAX. Here's a test to see if this applies to your machine: One Click To Crash Safari On Intel Mac.