Why does only Macintouch do these kinds of evaluations? Here's the conclusion:
The iMac G5 is a wonderful system, and we'd rather pay a few hundred dollars over the cost of an eMac to get one, but all the Apple hype about the G5 falls a little short when you see the low-cost eMac, with its slower G4 processor, pushing the iMac G5 in performance. The eMac is actually faster in several real-world situations, and that raises serious technical questions that long to be answered.
Adding the Mac Mini to the mix really changes the equation. For far less money than an iMac or even an eMac costs, you get excellent performance, silent operation and the ability to drive a big beautiful monitor of your own choosing, a critical feature missing from all but the Power Mac and PowerBooks. The Mini's one weakness is disk performance, which may make the eMac a better choice for video editing or heavy audio work, but it shouldn't be an issue in too many applications. For general home or office use, the Mini is perfect.
If you want the ultimate in performance - or multiple large screens - the Power Mac G5 is the way to go, although we have some concerns about reliability with the liquid-cooled 2.5GHz model and would probably stick with 1.8- or 2.0-GHz systems.
PowerBooks are nice, but pricy. The big advantage you get for the extra price of the 12' PowerBook is the ability to drive a larger external screen in dual-display mode (up to 2048x1536), although the built-in screen has the same 768x1024 resolution as the iBook.
The 15' PowerBook is an ideal mobile machine, and it can drive a big external screen on a desktop and use FireWire 800 to get disk performance more on par with a desktop computer's. This lovely laptop costs about four times what a Mac Mini costs, however, making it an expensive option for its portability and performance, and it's not as compact as the jewel-like 12' models or Mini.
The 17' PowerBook strikes us as an expensive alternative to the iMac with better portability and battery power.
One last factor is the G5's support for 64-bit processing, which is supposed to get a boost with next year's Mac OS X 10.4 'Tiger'. Theoretically, this may be an advantage for the iMac and Power Mac G5 models, but the real-world advantage for general applications is questionable at this point.
Ric did miss a key point -- almost everything that's true of the Mac Mini is also true of the G4 iBook. The main drawback of the G4 iBook is its slow graphics card and the inability to drive an external monitor at high resolutions. If Apple does a G4 iBook refresh in the next month that issue will be resolved.
The other part of the story is that the G5 is a crummy CPU. Hot and not all that faster than a G4. It really feels like a desperate marketing gimmick. There's reason to hope that the next generation IBM replacement will be better, but we're talking 2006. The good news from my perspective is that the inability to replace the G4 means Apple systems have a longer than usual lifespan (software vendors have to write to the G4 standard).
For anyone needing a machine and not doing video editing, the Mac Mini looks awfully good. For video editing the slow hard drive is a problem on the iBook and the Mac Mini. The (yech) eMac is a good solution, or a G5 iMac (toggle to high performance when doing video editing -- shades of toggling my original 8086 PC!), or a refurbished 1.8GHz PowerMac (need to have a monitor, takes up lots of room).