From Premiere to Mac and FCP
 

I might have an opportunity to move from a PC/hardware-based editing system to a Mac for a very reasonable price.

This would also mean moving from Premiere to Final Cut Pro.

What would I gain, what would I lose? What about the learning curve, would I have to start from zero?

How does a double-processor G3 work as an editing station with FCP ? Would I have _real_ real-time editing ?

To the best of my knowledge there are no dual processors G3's. Do you have the specs on the old computer you're thinking of using? What version of FCP? What type of projects do you edit?

I'm pretty sure you really meant dual processor G4, right?

I moved from Premiere to FCP myself several years ago. However I was using the Mac version of Premiere (if that matters). The transition was very pleasant for me. FCP is just a much nicer environment IMO. Visually the interface is much more attractive. And funtionally it seems better as well. But I think the concepts are all pretty much the same, it's just a matter of learning all the menus. If you get one of the many good books on FCP it shouldn't be difficult at all.

As far as the realtime effects, I'll leave that to someone else. I'm still on FCP 3 with a single processor G4/1.25 ghz and 1ghz powerbook. You only get realtime effects if you turn off external video with FCP3, and they are only at draft quality. You still need to render to see the actual effects on your NTSC monitor.