I use Citrix to access my school's accounting software. I have been thoroughly pleased with Citrix, firstly in that they HAVE a Mac client, but also in the fairly smooth Mac integration. I can copy to the Windows clipboard and it fills the Mac clipboard. I can save to the Mac desktop with ease. I can open Excel files on my Mac into Citrix. The software auto-updated for me in a completely transparent fashion. Other than the fact that I see Windows apps when I use it, it has been very solid software.