I see strange things happening with state-of-the-art uSD SDHC cards like the SanDisk Ultra 32GB SDHC I and  SanDisk Extreme Plus 32GB SDHC I in my Gumstix system (crystal@parlor).
With the latter I seem to have problems when rebooting the system, I always have to unplug and plug in the power connector, otherwise the system is stuck after the last messages:
Will now restart
Restarting system
With the first (SanDisk Ultra 32GB SDHC I) I seem to get occasional filesystem errors after a cold start, after rebooting one or twotimes these errors go away and the uSD card seems to work, also rebooting works. Fsck doesn't find any fs errors.
When I go back to my old (small and slow) uSD cards it always works, same rootfs, same kernel. So there can't be anything else than the uSD cards itself, causing the problem.

Has anybody of you seen similar effects? This is really confusing me currently. Can anybody recommend fast 32 GB SDHC cards which work reliably on a Gumstix DuoVero system?

My partition setup is the same as recommended by Gumstix (http://gumstix.org/create-a-bootable-microsd-card.html), it used to work with other (smaller) cards and Gumstix Overo systems for years, e.g.:
Kingston 16GB class10
Kingston 16GB class4
SanDisk 16GB class10
Pretec 8 GB class4