I am using a droidx right now and am also looking to upgrade. I love my phone it has hdmi out cable, the screen is big and beautiful colors are vibrant.
I've been looking at the iphone 4s, and was settled on that but now, I'm unsure. There are two phones coming out droid 4, and galaxy nexus. If your looking for an actual keyboard your only realy option is the droid 4. I believe it comes out december 8th.
The other is galaxy nexus which boasts the biggest screen for droid atm that i'm aware of. I believe its 4.2 inches and has better resolution then the iphone 4s. It also is the only phone that has the brand new android operating system ice cream sandwhich and it looks sexy. The insides are comparable if not slightly better then iphone 4s.
My problem with droid 4, I don't like physical keyboards on phones so I wont get it.
My problem with Galaxy nexus reviews have it as fealing "fragile" and its big so if you have small hands it might be uncomfortable. Also its a redone OS so there will probably be bugs, my biggest issue with it is that the camera is 5 megapixels. All other phones are 8 megapixels it also takes 720p video which isn't bad but its not best.
Iphone 4s- My main concern is I have a droid, i like the droid I can do stuff with the droid because its pretty open. Iphone is apple, apple is constrictive in some things, and I hate proprietary peripherals. Apple also is over priced. With all that said. Screen is smaller but seems brighter has better camera then Galaxy Nexus and takes 1080p video.
Its between Nexus / Iphone for me. I wont decide until the nexus comes out its rumored to be available december 8th. It keeps getting postponed though, its been released in UK and Canada already.
Hoped some of this helped.