So my main question is which one should I get and what ROM should I use? I haven't been able to see any real features to any of the alternative ROMs - what features do each of them have, etc.
First thing: 1000 or 3000? Basically, it's a matter of having the builtin hard drive or not. If you plan to load tons of music or movie files, or other bulky data files, or if you want to be sure that you'll never, ever run out of space when in an installation frenzy mood, then go for the 3000. On the other hand, if you want a cheaper device, and can live with having your data and third party apps loaded on a SD card, then the 1000 seems a good choice. It really all depends on what you plan to do with the device...
Now for the ROM. Since the alternative ROMs are only in (early) beta phase (OpenZaurus, Cacko...) on the 1000/3000, there hasn't been yet any complete review with comparisons of the pros & cons of each ROM on these devices. All in all, it's mostly small changes in look & feel (Cacko), slightly different applications (OpenZaurus), and integration of stuff that you otherwise have to install on top of the Sharp ROM. OK, I oversimplify things, but basically, don't expect a revolution when switching to a new ROM, mostly an evolution, it will still be the same hardware...
I'd suggest first sticking with the Sharp ROM for a while and find out which accessories work fine with which device/ROM combo before buying any (especially for the Wifi and Bluetooth cards). That might give developpers enough time to polish the other ROMs, and you'll have gathered enough knowledge to avoid the common traps and pitfalls of the Zaurus devices...
I plan to use it mostly in a PIM capacity
You'll quickly discover that the builtin PIM apps on the Sharp ROM (even once translated into English) are not very good (read: slower and less powerful than, say, your typical PalmOS PIM apps). You have third party apps, though (Qualendar, Ka/PI & Ko/PI, etc.) but each solution has its pros and cons, and depending on your typical needs you might or might not find one to suit your taste.
but of course it'll be quite handy for wardriving and such as well.
A few users have reported some success when using applications like Kismet or WellenReiter to do some wardriving, but other users (including me) have troubles finding the appropriate version & settings to achieve any useful results... Better chose wisely your WiFi card if you plan to make it work fast and painless!
Is there a way to turn it into a GPS somewhat like on more expensive cars that will show maps of wherever I am and directions to wherever I want to go?
There are some more or less advanced (in "early version number vs. stable application" as well as in "crude/simple vs. refined/powerful") GPS applications out there for the Zaurus, but nothing that would come close to, say, Tom Tom Navigator with vocal guidance... And of course you'd have to find a suitable GPS, there's no
simple way to connect a serial GPS to the Zaurus and the bluetooth stuff isn't builtin, so there seem to be some glitches when using bluetooth on the Zauruses... I didn't explore this area much, though, this might be worth investigating fully!
Also, I know from other threads that there is an app for subways in some cities, but it didn't have a Japanese data file. Is there a program that can plan routes on the Japanese rail system?
UbahnNav is a great tool - if there's a data file for your city, that is! I almost got to the point of writing a (simple) version with the JR Yamanote line in Tokyo, and would have added the other subway line later, but I won't be traveling anytime soon to Tokyo again so I've put that project on hold. I did read the UbahnNav docs, though, and it doesn't appear to be an impossible task, the thing that I would have missed were essentially the time schedules (to know the time between two stations)...
And of course, my main concern is with OS X synchronization.
I've read here and there stuff about MacOS sync, but as I've no Mac (yet), I can't comment on that subject. Syncing in general isn't an area where the 1000/3000 Zaurus is overwhelmingly good, I'd say.
All in all it looks like a wonderful little toy that I wouldn't mind using as my PDA as well as so much more.
Well, right now I'm not impressed by the PDA (read: PIM apps) use of the SL-C3000 Zaurus. For the "so much more" part, it's brilliant, but not for the PDA part, I'm afraid!
(And I can do some development for it too )
That's one of the promising paths I have to explore. I've been able to install some cross-compilation tool chain on my Linux laptop, and also to install a Qtopia development environment on the Zaurus itself, so I hope to be able to also do some useful stuff. But that's needed, unfortunately, as the Zaurus, "as is", has a lot of shortcomings... But it's a hacker's dream made reality, so it's sooooo had to resist the urge getting one!
