I owned a 1.25GHz PM G4 single-processor for two or three weeks. In that time I upgraded the RAM from 768MB to 1.25GB, and installed a Pioneer 106D, so I had dual opticals with both a Combo and a Superdrive.
The single-processor PM G4 felt amazingly fast. My previous desktop was a 700MHz eMac with 1GB of RAM and Pioneer 105 Superdrive.
I sold that PM and bought my current desktop, a 1.8GHz PM G5 single.
Although wide doesn't own a Mac yet, he knows what he's talking about. If you snag a good deal on a G5, you'll likely be happier than if you got a G4.
When G5s first came out, the speed tests had dual G4s beating single G5s. Now that some applications (notably Final Cut Pro) have been updated with G5s in mind,
my single G5 is pulling even and passing up dual G4s.. Compared to my computer the 1.42GHz dual G4 is faster, but the 1.25GHz dual G4 is slower. This is a trend which will continue, because as Dont Hurt Me has said a bunch of times, G5s are now and the future; G4s are the past.
As far as expandability of G4s compared to G5s, consider this. The 3rd and 4th hard drive connection built into G4 towers is ATA66. That's slow because modern IDE hard drives are ATA100 and ATA133 (the latter is more than twice as fast as ATA66). You have to add a PCI card to get ATA133 speeds from the 3rd and 4th hard drive bays.
It's exactly the same way with the G5. You need to add a PCI SATA card to add a 3rd, 4th, 5th 6th and 7th hard drive inside (with TransIntl.com's Swift Data 200 / ProMax's SATAMAXi system plus Wiebetech's G5 Jam).
As for the second optical drive, it's true that it'd be nice to have another one in the computer, but I have a FireWire case with a second optical drive in it (it's the CD burner that used to be in my eMac before I added the Superdrive to it). I've connected the second optical drive only once. I suppose once I get a combo drive it will be nice to duplicate DVDs that way, but as it is I create disk images of all the movies I make, and burn copies from those.
One last note about expandability - PM G5s (all but the 1.6) have a hands-down advantage in RAM capacity.
crowdaddy said:
By the way, what is the advantage of having a dual boot with OS 9?
OS 9 bootability is essential for everyone who needs a new Mac but has to run legacy applications. Classic in OS X doesn't work for many apps. People have to run legacy programs because either OS X versions don't exist yet, aren't as good or better yet, or they're simply too costly to upgrade.