The Rezound is a really good phone, if it has a weak point it is the battery life, the screen is amazing but sucks power like nobody's business... expect only about 2.5 hours of screen on time using a standard battery with excellent signal, 3.5 to 5 hours with the extended battery. As far as stock, it is very stable and functional, custom ROM choices are pretty varied especially since the RIL has been cracked, there are a wide range of choices, probably 20-30 fairly solid ones but three or four clear front runners right now, but that changes on a weekly basis it seems, currently only up to ICS with custom CM10 JellyBean build in the works.
The Inc 4G is a solid performer, it has newer hardware and is more efficient and can provide about 4 hours screen time on the standard battery. I have not dug into the 4G too much but it has been rooted (sort of) but not S-OFF'd (officially anyways, there is lots of work on this and some devs claim to have done it but are not releasing it yet), custom ROM choices are basically either ViperLTE or UltimateKangBang LTE and that is about it currently. Note that newer firmware's broke the ability to unlock via HTCDev, thus root is impossible at this time with some versions but I expect this limitation will be bypassed soon or has been recently.
Don't count out the new HTC DLX/Butterfly/DIX to be announced on the 13th, also the new Motorola Razr M & HD series phones are pretty amazing devices, have a couple M's in our office and they are just rock solid with no issues at all as of yet. Be wary of the Samsung GS3, it can be a solid device but almost everyone I know personally that has one had to get a replacement (or in one case three!) either for overheating or microphone problems.