May I put in a vote for 3.5.4/GPE for the collie please?
I have been using the GPE versions of OZ 3.5.2 and 3.5.3 in conjunction with Klaus Weidner's pocketworkstation (debian/sarge) on an SD: most extra programmes, such as TeX, xdvi, xpdf etc, can be run directly in the GPE x-windows environment via his command "Cdr". This seems preferable to running pocketworkstation on in its own, even with a matchbox window manager, or of running it through opie and xqt. I hope that TeX, xdvi and xpdf will eventually be added to the OZ feed, since according to the last OE newsletter at least TeX is available through OE/bitbake. I am also looking forward to the latest version of minimo (with the forwards and backwards arrows working). To enable the escape and function keys for emacs and vi in 3.5.3/GPE, I had to comment out two lines near the end of kbdconfig in /etc/matchbox and remove the "keylaunch" ipkg (thank you, lardman).
Otherwise, GPE seems extremely nice. The other currently available x-windows rom for the collie, pdaxrom, appears at present not to be in a very usable state on a collie.