Everyone has their own opinions. Here's mine:
We usually spend little time in MK since we go to DLR alot (and it's so much better) We spend most of our time at AK and EPCOT.
Personally I think ToT at DCA is better but I would still do the one at DHS (it is different)
POC so much better at DLR but also worth checking out at MK (if the line is short)
Fantasmic-much better at DLR.
Soarin'-until they change it (if they do) it's exactly the same at DCA and EPCOT . This is one line you can skip IMHO
Small World-different at MK, much better at DL.
I think the Tiki Room at MK is better than at DL. I'm a little tired of the DL version.
Space Mountain-different-worth riding both versions.
Star Tours-same once you get on the ride.
As some PP have stated we are usually fine with 1/2 day or so at MK. We do the rides the DLR doesn't offer. We really enjoy the waterparks and usually spend 2 days there. Last year we did 3 days. So cool!
Also, we don't spend a whole lot of time at DHS either. We do ToT & RR mostly. DHS does have some great shows. B & B, Indy (not the ride, the show), LMA etc. I could probably never go back on the Studio Backlot Tour and be a happy girl!
Oh, and the Muppet Movie at DHS is the same as the one at DCA.
HTH