What I want to ask is just hom much faster than my power flyer is this?
Obviously it depends on the speed you manage to get out of the power flyer atm. It is said that power flyer can get upto 7-8 MB/s, but often the actual speed is much lower.
I'm guessing it'll be sans the CPU overhead which is a good reason to use it, but will it be any faster transfer wise if I slap a good drive on it?
With good drive you get 8-9MB/s, in optimum conditions very close to theoretical maximum (over 9.5 MB/s). This is with 1-2% CPU usage.
Obviously this is just the maximum transfer speed. The seek speed affects the performance aswell. Older SCSI hdds are actually slower in this regard than modern IDE hdds.