I just went from my X (running Vortex) to the Maxx a couple weeks ago. I would not have switched, but needed a world phone. Haven't rooted yet, may wait for ICS before I root.
It is large, but still fits in my front pocket fine (I don't like holsters)
I have the otterbox commuter and it works well without adding much bulk (My X never had a case)
Otherwise, its a bigger screen, better screen, battery life is better (and I had the extended battery for the X), and everything I have installed so far works great. Even installed colornote and restored from the datacard backup off of the X.
There are a few things I had on the rooted X that I have not found yet duplicated on the Maxx, but I haven't searched hard for them and I'm sure the devs will make it possible.