Welp, I just reloaded the SE image (A05), after having similiar issues with WM5. Mainly, I found myself having to constantly soft-reset the device in order to turn it on. No good that! I can't be certain, but it seemed to improve when I swapped out the battery with my spare, though I don't know why that would have any issue.
Overall, I liked the new OS, but found that many of my favorite apps and GUI interfaces were not yet compatible. Ultimately, that's what really led me back to 2K3.
Oh well, at least the roll-back brought me to the current SE ROM (I was at A03, prior). Now I need to wait for DELL to offer a fix and for my favorite apps to be upgraded.