I'll give my rundowns on the distros I've used (all on a C3100 except Sharp/Cacko). I'll probably leave a bunch out, but here goes:
pdaXrom
Pros:
-Built-in right click system
-relatively fast
-designed for the Z
-easy on-board compiling and development
Cons:
-Moving target
-Incompatabilities between the many flavors
-sporadic development****
-default install eats RAM like there's no tomorrow
-unique/broken/painful build system
-many outdated parts
-Unstable/buggy/"quirky" in many cases*****
Debian
Pros:
-Abundance of web browsers
-DEBIAN! (feels the same as the desktop)
-Constant updates
-large number of packages ready to go
-Easy dev setup
-"Standard" Linux feel
-Works with many things out-of-the-box (everything I have, at least)
-OpenOffice (SLOW boot, works OK after that)
-FF3 RC1 (in some obscere repo)
Cons:
-Sluggish, especially after coming from pdaX/Angstrom, but tolerable
-Install can be...interesting (maybe I just didn't think it through)
-No central, up-to-date, easy-to-use place with links to files, directions, etc (must dig through thread somewhat)
-Many different flavors (EABI, OABE, Andro-whatever the new one is)***
-not optimized as much as is possible
-apt is painfully slow on the Z
Sharp/Cacko
Pros:
-Stable
-Syncing capabilities**
-Opera
-GUIs
-Comes ready for many things out-of-the-box
-Supports BVDD
-Relatively quick
Cons:
-Difficult to make packages for
-Old
-No active development
-Covers up the Linux (IMO)
-Building custom modules is a PAIN (eg, kernel is a pain to get set up/configured, IMO)
-No updates
Angstrom
Pros:
-Up-to-date
-actively developed
-large-ish number of packages available
-easy to set up a dev environment
-much hardware works
-suspend/boot/etc works
-Mostly stable
-Native development/compiling is easy
-Easy to get kernel dev stuff for compiling modules
Cons:
-default images are lousy
-No real support on the forums; must use the mailing list
-Broken things (installing ipks to places other than /, for instance)*
*May be outdated info
**Not confirmed by me
***How about a new, barebones tarball, and people just make custom packages that install the tweaks and stuff instead?
****It appears that is changing, but still
*****Most bugs take only a minute or so to fix, but the fixes never made it upstream