The PowerBook G3 Series, also known as Wallstreet, the second generation as Wallstreet II or PDQ, and the first generation entry model as Mainstreet, is a very viable computing in an almost retro environment. With processor speeds ranging from 233 to 300 MHz with typically 1 MB of L2 cache (except the 233 MHz models with 0 KB/512 KB), it was a very capable computer with Mac OS 9.
Then Mac OS X came along, featuring a massive amount of bloat and several driver incompatibilities including the optional floppy drive and onboard video acceleration. Plus in 10.0 and 10.1, sleep mode was not supported properly. I installed OS X once. It lasted 20 minutes. Not only did it crash three times in that space, my USB card, which was the entire reason I installed OS X, didn't work quite right with the drivers on the included CD. Reboot into OS 9, erase 2 GB worth of files. Don't make this mistake like I did. USB isn't worth it.
Mac OS 9 is a speed demon in comparison to OS X on the same hardware. If you have the choice, go with 8.6 or 9.2.2 over X, whichever you prefer and/or have the RAM for (I've got 384 MB, so it isn't an issue for me). Software support, in my experience, has been flawless and insanely fast.
The Wallstreet shipped in many configurations including three screen sizes. The first series shipped with a 12" passive matrix, 13" active matrix or 14" active matrix display. The quality of the 13/14 is widely regarded as better due not only to the number of pixels (1024x768 vs 800x600) but also by inherent design. A passive matrix display is not as sharp as an active is, but they are much cheaper. The 12" also only had 2 MB of VRAM while 13/14" had 4 MB. You should also look out for 13" displays, as they had extremely. Fragile hinges. Really. Be careful.
The 14" model was standardized upon in the second revision and is mainly what will be covered here. This computer is heavy. 7.8 pounds. The center plating on the top and bottom is actually rubber coated steel. Not only does it look and feel cool (figuratively), but it really helps to dissipate heat. This computer generates a whole lot of it. My processor temperature sensor has reported temperatures in excess of 60 degrees celsius (or 150F). It has a very nicely designed heatsink that runs through the computer to help with cooling. As a rule, OS 9 is more power efficient than OS X is.
It also feels (and in person, almost looks) bulletproof, but maybe that is just the tightness of my replacement hinge keeping things nice. If I'm ever in a firefight, I'm taking one of these along [/sarcasm]. Seriously, though, it is a very sturdy computer save the somewhat fragile hinges, even on the 14" model. The display is a bit on the heavy side (three pounds, I read?).
As the purpose of these pages is to find ways old technology can be useful, I'll finally get to the real point: the sturdiness of this computer is impressive and if you are willing to invest in a pair of batteries, it would probably last for 8+ hours (I wouldn't know; my battery is completely dead. Won't even light up.). The display is subject to yellowing, though these can be had cheaply if you can locate a part number. I'm sorry, but I don't know the PN off the top of my head. If you pull it apart (not hard, just need a Torx T8 and a Philips screwdriver set), you can read the PN off the back of the display. If properly refurbished or better yet, you wait for a good one on eBay or other resources to appear, they can be venerable workhorses. Add a USB card, a 500 MHz+ G3 card, at least 256 MB of RAM and *shudder* OS X, you could have one of the most expandable portable Macs ever. Those intending to run OS X would be better off with an AirPort equipped Pismo, however, as WaveLAN driver support in OS X is virtually nonexistant.
That and a nice and clean one looks very professional. If only the Apple logo could be rotated to face the right direction. Then it would be the perfect OS 9 machine.