I think I'll have to do some confessing here:
We (that's me and a friend) have been making a living off selling PDAs.
But I always considered them toys.

We started at the time when the Palm III was FRESH and Psion RULED.
I saw one of the first Compaq iPAQs and considered it UGLY.

I only thought it amazing how many times the calculating power of a Commodore 64
incl. the Commodore's screen (320x240px, 1MHz, 64K RAM) they could put into a small box
without really getting much better solutions.

We made fun of people poking their little boxes with a small stick
and I never could figure out what real sense such a thing would make
except impress the neighbours.

Then our customers were thrown out of their jobs (we finished in 2003)
and demand drifted towards mobile phones.

A few months ago the GTD book re-awoke my interest in PDAs.
I found that doing everything on the PC just isn't flexible enough for my job.
And PDA software has advanced since 'them days of old'.

'Lots to see and enter text fast' are my aims now.

That's why I stock up on my arsenal of Psion 5, Sony UX50, NR70 (with the option of getting a NZ90 or NX73) and MDA Compact, MDA Vario and MDA Pro.

AND I've got the plan of keeping the best and dumping the rest in the 'bay'.
(Having too many options is a good way NOT to start.)

Psion and UX50 only do landscape (not very many lines of text to see).
NR70 has a crap keyboard.
The MDAs (=QTEK = HTC...) include a mobile phone (=nice).
MDA compact hasn't got a keyboard at all.
MDA Vario and Pro offer text entry via keyboard only in landscape mode.
All MDAs run with Windows Mobile. And I think there is no real good outliner for that OS, is there?

I think the NZ90 offers the best compromise of keyboard (small but backlit =fast texting everywhere), big screen (HiRes portrait, nearly 4 inch = more lines of text to see) and instant usability.
But it's quite a BRICK.

What configuration do you use to see as many items as possible and to enter text quickly on the PDA?
(Does anyone really use an external keyboard?)

- - -
Just wondering:
In a Bonsai outline
in Options > Outline Prefs > Outline Fonts
the font sizes seem to vary according to the PDA:
Sony UX50 (Palm OS5) 8 sizes.
Sony NR70 (Palm OS4.1) only 3 sizes.
How many font sizes does your PDA offer?
How many (readable) lines can it display?