The only application that I was sad to lose going to the Mac was Beyond Compare - but finally there is hope. DW is as close as it gets. At the time of writing this saving sessions is not in the application but is coming, as is the ability to connect via other protocols. I've tried Araxis Merge and Apple's FileCompare (it's hopeless) but this I think is the best replacement for Beyond Compare that I've found and comparatively priced.