The last time I got this engrossed in an MMORPG was Everquest over 3 years ago. I have since played DAOC, AO, AC, EVE and a whole bunch of lesser acronyms! None lasted more than a month at the most and none had me playing for 6 hour stretches.
I am not sure where the idea's of lack of content comes from, this game is gorgeous and the content is huge for a MMORPG, it actually has a storyline!
Yes combat is not exciting as a solo player, this game is not a solo game, you have to group. One of the problems is that you really have to group with people who know what they are doing! Yes you can group and simply keep pressing auto-attack, or you can group and try to battle really really tough monsters by skill-chaining, using your own skills in interesting ways (ie sneak and WS).
Yes this game is an xp grind in many cases, however it is a very pleasant xp grind. Levelling is nowhere near as tough as other MMORPGs, you can gain xp at roughly 1000xp an hour in a semi decent group, up to 2000xp in a great group. Even at high levels this is only 5-10 hours of game time to go up a level. Unlike EQ which was weeks of game time even at mid level.
As for quietness I found it quiet when I first started, however I have built up my friends list at over a months play. My text now scrolls faster than I can read, linkshell chat, tells, party text it is very loud and you can see why no one shouts!
I would recommend the monthly free trial and it is currently the best MMORPG on the market. We shall see how it fares to the upcoming EQ2, UO:X and WoW!