Unusual for a non-Mac user to go buy a mac
I don't know that we have many other mac users on here at the moment, so you might be better off googling to find a support forum.
1. You have a range of browsers available on the mac, each do different things.
IE will do one thing (and even worse in some cases than PC IE), while Safari does another, and Firefox on the Mac should be pretty well the same as on the PC.
Mac Firefox:
en.www.mozilla.com/en/firefox/all.html
2. From experience, the range of FTP clients are more diverse than the browser wars. It will be a case of trial and error I'm afraid for a Mac FTP app that does all that SmartFTP does.
www.pure-mac.com/ftp.html
I use Bulletproof FTP (and occasionaly SmartFTP) on the PC, so it may be that Bulletproof for the Mac might be one to try.