My apologies for any confusion. I didn't intend to imply that a 500MHz G3 with a Rage128 and a 100MHz bus would numerically, on paper, outperform a 1000Mhz G4 on a 133MHz bus with a Radeon 9000.
Of course if you get a raw CPU benchmark, a 1000MHz G4 will be much faster than a 500MHz G3. I suppose that seemed obvious enough to me not to have to say it. At the time, I was using SETI@home Classic and, sure enough, the TiBook rocked at fast fourier transforms, which I'd bet fit within its meg of L3 cache. (I believe BOINC had come online by the time I got the Pismo, I don't remember if I ever used SETI Classic on the Pismo, but I did on a blue G3/450 tower, and, the TiBook was, as you'd expect, much faster at raw out-and-out compute that only touches the CPU.)
My, admittedly anecdotal, and it appears literally nobody else had this kind of experience, is that the TiBook buckled immediately and hard once you started to do certain types of difficult work on it. Mine was "looking at photos." (In OS X, which was my daily OS at the time, because of convenience and the web.) It was bad in iPhoto with 2-megapixel JPEGs, which were a common file format and size in 2002 when the TiBook/867-1000 launched, and it got worse when I got a camera that could produce 6 megapixel RAW files.
The TiBook was solidly "fine" at mostly everything else I did with it. Email, internet, word processing, page layout, and even (because this relies more on achieving a certain consistent throughput, which became trivial in 1999, than random i/o perf) ripping DV tapes and simple standard def video editing with DV files.
In retrospect, the problem was the disk drive. The TiBooks (and first-gen AlBook) all shipped with 4200RPM hard disks as stock, because it wasn't until later that there were two suppliers of 5400RPM laptop hard disks, at which point Apple adopted them for PowerBooks.
From a technical perspective, I could have worked around the problem by using an external firewire hard disk, or buying my own 5400RPM laptop hard disk and installing it. I didn't have the means (or, to be honest, I was a literal child at the time, so, the knowledge) to do that.
It really, really, soured the experience of using a machine that retailed for $2,799 and was under three years old. I've thought for years that the $2,800 would have been better spent on almost any other combination of Mac hardware at the time. The scenario was, I don't know if this is unique, but it was one where the machine showed up one day largely in exchange for my coming along quietly with a big cross-country move into some much smaller living quarters. It's not exactly relevant here, but it's perhaps useful context for why I as a literal child even had a TiBook.
It suffered lots of random physical failures along the way, more than any other laptop I've had up to this point, and suffered a display failure I didn't have the means/wherewithal to recover from, so I swapped it for a pismo, which itself did have an upgraded disk installed. Between that and ho-hum normal 5400-7200RPM desktop drives in my 450MHz blue-and-white tower doing my photo work as fast as the TiBook, I don't think it was entirely unreasonable for Young Cory to come away with the impression that G4s were bad machines.
That was, of course, bolstered by the bad physical reliability of the G4 I happened to have.
And then by the fact that the slowest MacBook Pro that ended up shipping, the 1.83GHz Core1Duo model, also managed to outperform my TiBook at the photo tasks.
A faster disk would've resolved a lot for me, but I still think, given that my workload in 2005 isn't even remotely comparable to what most people are doing on vintage OS 9 machines today, that recommending a PowerBook or iBook G3 over a TiBook today for that need is reasonable. You miss out on the upgraded screen and the newer graphics, but you're not really missing out on any real-world performance improvements for OS 9 apps. I'm not convinced that OS 9 gaming on TiBooks is a thing a lot of people are interested in, mostly because we'd hear about it if they were. From what I can tell, most of the vintage Mac gaming people are either fine on Pismos and iBooks, or they're doing "maximum possible" PowerMac G4 configs.
And if you wanted to use apps that ran in OS X and needed a lot of horsepower anyway, you could just get much newer PowerPC Macs (such as the last round of G4s, as suggested above, or G5s) or, heck, Macs released up through 2012 will run 10.6, which still has Rosetta.
Re Radeon 9250 and Core Image: Whoops, sure enough. I was mis-remembering both some mini specs and the Core Image information. The second group of Aluminum PowerBook G4s supports CoreImage, and the 1.42GHz eMac supports it with a Radeon 9600, but only some (17-20") of the last generation of iMac G4 support it, no G4 minis support it, and on the PowerMac side, of course the MDDs support it, but talking about PowerMac CoreImage support is a little moot as you can install newer graphics cards into any PowerMac G4 minus the Yikes.