the main feature that is worth some attention is the DPM, this is project from the celinux consortiums work groups and is an advanced super set of cpu freq scalling.
basically it scales every asspect of the system, such as mem speed, bus speed and cpu speed as well as dynamic voltage adjustments. this is what truley saves power and is the reason i loved the over clocikng tools in winCE (where you could fiddle with the registers directly and change the vcore and bus speeds)
at the moment it exsists as a set of patches agoints a 2.6 kernel and includes support for the pxa processors (basically all of the Z), and as far as i can tell it applies cleanly
when coupled with cpufreqd (IMHO the best cpu freq scaling app onec you work out its crazy syntax and mindset) it should allow for highly optimised power usage and give you back at least 10 mins, i would say thogh that your milige may vary but that you can likly get more than that.
what else dose this mean to us, well have a look at the main supported processor:
Mobilinux 4.1 appears to initially support Freescale's ARM11-based MC9328MX31 SoC (system-on-chip processor), also known as the i.MX31. The i.MX31/i.MX31L shares the same core as Freescale's highly integrated MXL "mobile phone on a chip."
this means that patches for the iMX.3 should appear in the kernel, it already boots however its options are what i would call "sparse" this may be because of the lack of boards and specific tmeaks for said boards bassed on this chipset however if you get a chance try "make ARCH=arm menuconfig" in the kernel source and have a look around, you will find that some hardware is not avalible for arm while other options are