Speaking of CPU speeds, let me put a question out on the floor. When you think of Sun workstations and servers, do you think of high performance?
Would it surprise anyone to know that up until a couple of weeks ago, the fastest UltraSparc II CPU available in any Sun machine was 440MHz? Even now, their high-end, million-dollar-plus servers use only those CPUs. Sure, they have up to 64 of them, but they're only 440MHz.
As of their recent announcement of the UltraSparc III chip, Sun now has a small selection of workstations and servers running up to (gasp) 700MHz.
There are many other aspects of a CPU's architecture that determine its performance relative to any other CPU. The G4e (or G4 plus or whatever) sounds like it's going to kick butt.
Personally, I think I'd be very happy with a Dual Processor Mac running 700 or 800MHz G4e CPUs. It would rock.