mp3/video and text editing are not thigns that really stress any device; you could do those on a Apple Newton MessagePad released in 1993
(yes, there is an mp3 player made for it
Hmm, trying to think of what other differentiators; as a mobile developer I find, as always, its the feal and controls; if the dev ice weants to be thumb typed or keyboard-typed is a big one, and the mouse; sone of the tumb-mice are totally unusable and render the device terrible. I'm thinking of the older Sony UX .. see pic: http://www.barnardmicrosystems.com/sony_ux390n_1.jpg -- the keyboard was basicly unusable, and the mouse terrible; the touchscfreen and high res on that device was fantastic, and a decent cpu for running various things, but the controls and thickness made it bad.
That all said, the N5 is _sweet_
So it depends what apps really -- given a full Windows UMPC, you can run Windows apps on their (or sometimes linux, etc, but often with trouble.) But as you say, no gaming controls; great for just running unemulated PC games (Baldurs Gate, no need for GemRB!), but you'll never get any value out of emulators or action games on a UMPC.
I guess its a quesiton of trade-off -- do you want to give up the convenience of running Windows (assming you want a Windows oriented device or applications), for better controls? ie: Your core apps are essentially the same (same browsers, functioanlyl same text editors and media players), but its the apps that push it that differ; Emulators like MAME, Genesis etc will be fine on Pandora and unusable on a typical UMPC, but a typical UMPC can rn windowds and just jack in any old GPS USB widget and be good to go.
I don't think its an easy answer.. as Prometheus put .. it _very_ much depends on what you need to do and how long you can wait
jeffphone