I used to have an csppc, did not use the ppc side that often and got fed up with old scsi disks and scsi to ide/sata converters so I bought myself a fast ata 4000 for my 3000T
I went from about 30mb/s to 6-7mb/s
Can't say I notice any difference on day to day use but when I transfer big files there ofc will be a slowdown and I miss my ppc a bit.
The fast ata is a very nice card and it's easy to setup and get working.
Sure it drains a bit of CPU but it ain't like the system can't be used while you are transferring files.
If you are like me and tired of those old and loud scsi drives and want an ide/sata configuration with Maby an ssd drive or any thing I would say go for it.