First off, please remember that forums are typically a morass of complainers, trolls, meme-queens, i-quitters, and white knights. Be sure you filter responses with that in mind.
That said, I am really enjoying Tera! I've played every class except sorcerer to levels 16, 18, 23, 29, 33, 38, and 45, so I can't give you any advice about end-game. However, I can tell you that this is the first time in any game I've played (WoW, Rift, LoTR, DDO, Aion, AoC, SWTOR, GW1) where I've had such a thoroughly entertaining time leveling, questing, grinding, exploring, experimenting with new classes, and creating new characters/faces. Here are some reasons I fell in love:
1) Each race and gender has significantly different armor graphics. Love them or hate them, they're almost universally very creative, interesting, detailed, and ornate. Getting new armor is very exciting, and a great many race/armor combos are truly stunning.
2) The graphics are not mass-appeal graphics. The system requirements aren't outlandish, but they didn't pull a WoW/ToR and make the game look like crap so people could play it with Windows 98. The game's beautiful. The rendering issue you mention depends largely on your graphics settings; mine sit at max and I hardly notice it at all. All the same, even without the textures completely rendered, they look better than most MMOs. The amount of detail is something you really have to see in game to believe.
3) Everything you've read about the questing is true. They're pretty mundane and repetitive, tbh, and do feel a little grindy. Fortunately, this is mostly compensated for with open-world dungeon zones that feel huge and epic, lots of world bosses as parts of quests and just for EXP, and the fun of the combat system. At times I'll get bored with questing and just go kill BAMs for awhile. Also, there's a decent amount of cut scenes included for main storyline quests; this is a nice departure from WoW where you had to kill Deathwing/Lich King to get a fugly 20-second cinematic.
4) Having played the GW2 beta weekend, I can assure you that GW2 is not coming out at the end of this month. I'd be shocked if it's out before Thanksgiving. There are lots of bugs still, and I honestly wasn't too impressed. If you're concerned about having things to do at end game, then GW/GW2 is not the game you want to play; there's virtually nothing to do at end game.
I'm spending the time to tell you all this because I bought the game with low expectations and was very surprised - pleasantly so. In fact, I cancelled my wow subscriptions after 6 years of playing. It's worth the money. Community can make a big difference, too, and I would suggest Celestial Hills if you're looking for immersion, some light RP, and lots of active guilds with very few douchebags.