I only have an M001, which has the advantage of being popular so there are people modding it, and some people working on a clean implementation of the linux kernel (groups.google.com/group/vt8500-wm8505-linux-kernel)
If you want to do some kernel device driver writing, binary reverse-engineering, or port Android 2.2, those are all good things you can try on the M001 (or the Walgreens tablet, same SoC.)
However, there are better cheap tablets. $200ish can get you one built around the TI OMAP3 platform. One is called the Wits A81E. For a lot of tinkering, that's probably a much better buy - Android 2.2 already runs, you get a Cortex A8 instead of an ARM9 (so it -will- run recent Ubuntu versions), and the OMAP3 SoCs have properly open sourced and mature linux drivers. I haven't actually used one, though.
It really depends on what you want to do with it, I guess.
If you want to do some kernel device driver writing, binary reverse-engineering, or port Android 2.2, those are all good things you can try on the M001 (or the Walgreens tablet, same SoC.)
However, there are better cheap tablets. $200ish can get you one built around the TI OMAP3 platform. One is called the Wits A81E. For a lot of tinkering, that's probably a much better buy - Android 2.2 already runs, you get a Cortex A8 instead of an ARM9 (so it -will- run recent Ubuntu versions), and the OMAP3 SoCs have properly open sourced and mature linux drivers. I haven't actually used one, though.
It really depends on what you want to do with it, I guess.