Well...my gf and I have both. As time goes on I find myself picking up the Imagio more and more.
Hardware:
Droid has better CPU and a physical kb (you already knew that). Screen resolution is CRAZY!
Software:
Check moto and/or Verizon forum for some bugs started to surface up. Mine, speaker cut out for no reason and the phone ring/notification goes to almost silent. I have to reboot every 6 hrs or so otherwise I cant hear it.
Email:
Droid - You can view attachment (pdf, pic...) but can't be save unless you have doc2go (so i was told). you can't forward attachment either (in my case non-gmail). Imagio - Everything works for me.
Media:
Droid - music player, haha...what a joke! Probably no biggie to some. Photo viewer, no multitouch. Browser, no multitouch (damn, sh!t piss me off)
Imagio - HTC flavor of player and zoom bar.
Phone dialer:
Droid - basic raw Android, no smart dialing, no call history grouping (remember WM5, yup same sh!t)
Imagio - HTC flavor, hell yeah sure beat winmo dialer!
Tethering:
Droid - None for now. Expect to pay $15 extra next year to VZW when they support it.
Imagio - yes, hit this up
http://forum.ppcgeeks.com/showthread.php?t=90702
IMHO, the Imagio just works for me at this point as some reviewers called winmo is just like a pickup truck nothing sleek or fancy about it but it just works. After you disable some carrier craps and tweak it a lil bit, it's a beautiful thing.
We're still gonna keep the Droid around. Hopefully some good apps come along to change that raw looks.