Is this game centered mostly on PvE or PvP, or does it balance both?
Also, are there a lot of dungeons, and are they good? What is PvP like? Is it done on the open-field or in a separate area? How does one level up and get gear upgrades? Is the game Pay to Play? Is it easy for a character to transition from PvP to PvE? How's the story (honestly, I didn't think the cinematic was very good and just seemed a bit.. cheesy)?
I'm considering this game, but I've been disappointed by nearly every game that's come out recently for the PC, especially MMO's, and RPG's. I'm willing to try it out simply because it has a large ToJ following and looks promising.
Thanks for your help. Oh, and I looked at several of the links you provided and the wiki page - thanks for those, it's very useful.
I only got to level 11 and did not actually pvp nor go to a dungeon or raid yet, however, I'll give my thoughts on it so far. I expect the game to be pvp centered while pve will be padded a bit by rift encounters. I don't know how to say it but it's like everything that works in other typical mmorpgs is in rift and is polished but I get the feeling it's not very "glittery" nor is there a huge amount of content.
Is it done on the open-field or in a separate area?
There are PVP and PVE servers for each of those.
How does one level up and get gear upgrades?
Aside from the typical ways you can get gear through fighting Rifts too. Rifts give their own currency with which you can buy gear. There may be more I'm just a newbie.
Yup it's by subscription. They do have some deal where you get a buck or two off (locked in as long as you don't cancel) if you pre-order or something. Check their site I'm not buying it I'm just playing in the free open beta come the 15th.
Is it easy for a character to transition from PvP to PvE?
Uuuuuuuh I could be completely wrong but it looked like you could transfer a character at any time. I base this on 5 seconds of clicking past the server screen, noting it looked like you could, but not trying, and not caring to check further into it XD. Can't check now the servers aren't up of course. Google is everyone's friend! (well except maybe the Chinese XD

)
How's the story (honestly, I didn't think the cinematic was very good and just seemed a bit.. cheesy)?
IDK about cheesy (what mmorpg are we comparing this to?

) but I'm not feeling a strong plot is going to be forth coming. Defiant/Guardian sides and the main plot point, Rifts are the result of a seal on ancient evil breaking, ho hum, are typical. There where some cinematics at start and of course background info in text. Story seems to do it's job but nothing engrossing so far.
For my part (if I was playing past the beta) I can see myself tinkering with character combination for a bit trying to perfect a hybrid that I both like and is effective in pvp. Don't let the ad's mislead you though the combos are definitely finite. I expect there will be several dozen or so "go to" builds with tons of subtle personal variations in a few months. Many combos simply won't work as well together as another resulting in this. For example, if I read the ability trees right, as a warrior you can only block with a shield (or with one special ability). This makes all blocking abilities useless if you use a two handed weapon or if you use a shield it makes two handed abilities useless. Still Rift has more room for class customization than any other mmorpg I've seen. I expect the game will attract the Warhammer type player but if it endures will be based on if it has decent end game content (which no one has seen yet).
In my opinion try the game if you want PvP, class customization and some Rifts to break up quest grinding. Rift is nothing revolutionary it just borrows a lot of things that work. Also I keep hearing Trion listens to it's players, take what you want from that.