I'm around 2 hours and 15 mins into the game, and so far I am impressed, very impressed. I have always been a huge fan of Carmack though, to me the guy is a genius.
Anyway, to answer your questions, the combat has been in the middle so far. Not slow, but not frantic either. They seem to be throwing a good mix of guys that stay at range and pick at you and guys that are melee/shotgun that absolutely close in on you and try to facerape you. The guys that close in are pretty quick and good at it, most of them do NOT just run in a straight line waiting to get ripped down. They zig zag left and right and depending on who you are fighting, they vault off walls and use pipes above them to swing forward, etc. It's pretty insane.
The environments are stunning. There is a noticeable texture pop in, but I don't think there is ANY way to avoid it with how ambitious Rage is. Even with the pop in, the game looks gorgeous for being on a console. Of course it will not compete with high end PC's at all, but that's to be expected. Carmack is an engine designing genius and the game looks to me, like the best looking game the 360 has ever seen. So far it's been running at a steady framerate with no noticeable slowdowns. The world is stunning and great to just sit there and look around.
As far as the interface, it's clean and functional. You have your standard minimap in the upper right, gun/gun selection in the bottom right (right bumper), ammo selection on the bottom left(right bumper), defibulator charge in the bottom left next to ammo. Hitting the back button will bring up the standard interfaces you have seen before for inventory, quests/journal, engineering and arsenal/armory which outlines what guns you have, what ammo you have for those guns and what armor you have. Overall it's all very easy to work with and works very well. It feels pretty RPGish actually in that sense.
It is a save anywhere system, which I am thankful for. The game actually does not auto-save very often that I have seen. It will save when you transition from outdoor to indoors and the reverse. but that's all I've seen so far. If there is one piece of advice I can give, it is to SAVE OFTEN, because if you die and your last save is the auto-save when you entered some bandit hideout 30 mins ago, then you are screwed. The load times seem fine to me, I installed Disc 1 to my HDD and it takes about 10 seconds to load an area I am going to and the same to load the Wasteland when I leave. You don't do a ton of that though, so far at least it's been pretty minimal.
Some of the cool things I've noticed so far is that for one, some guys wear helmets. A headshot will pop the helmet off violently and knock them down. The way the game handles guys getting shot and dying is pretty damn cool. Many of the melee guys that charge you, if you kill them while they are still coming at you, will hold their chest and stagger with continuing forward momentum for at least a few feet more, dropping their weapon in the process. They will then fall forward dead after staggering. It may seem like such a small thing, but it's an awesome touch and a nice change from the standard "shoot them and they just fall down" formula. Other guys you will shoot a few times and they then make some comment about being all fucked up, they start to crawl away or for cover while shooting at you from the ground, that's another very cool touch.
I can already see the card game getting me horribly addicted. I haven't even played it yet, but I have been collecting cards. I am already feeling that MtG like pull to get all the cards, assemble and awesome deck and whoop up on unsuspecting wasteland peoples.
While the game may not look very unique or new from the commercials and videos, it really does feel new. They seemed to really go out of their way to not just spit out some clone of what modern shooters are. So far it feels like a cross between Fallout and Quake but with vast improvements over either of those. Even though they are avoiding the RPG tag, and I do agree it is absolutely not an RPG, there are elements that very much feel like an RPG. Going through the beginning 2 settlements and talking to people, gathering schematics and parts so that you can build shit using engineering, the fact that you even have an inventory screen and a quest log. While none of these are "new", in this combination they feel really fresh.
The game feels immense. I don't know what the length of the game is, but it truly feels massive. It's 2 DVDs for the campaign with a 3rd DVD for multiplayer. I do know from interviews that there is a TON of side shit that you can do or just ignore. I believe I read that there is something like 26 different race circuits you can join to do vehicle racing, yet only 2 are required for the story. Which reminds me, so far I have only gotten to drive an ATV, but the driving feels smooth and responsive. It is a LOT of fun to just tear ass across the wasteland on my ATV with an afterburner on it. There's jumps and shit to mess with all around.
Since I am only in the beginning, it has been very linear so far. Story driven with a few side quests that I could have ignored. From what I understand, it will open up a bit later on, but it is not a fully open world game. There is always guidance and the main story with the side stuff supporting it. Whether it will feel incredibly linear or not, I don't know yet. It's too early to tell. I do know that I am definitely enjoying the shit out of it so far though.
I'm going to go back to playing, I can post more impressions later or tomorrow. If you guys have any other questions, ask away, I am happy to help anyone who is deciding whether or not to pick the game up.