A by-the-books isometric loot fest that fans will enjoy, but will do little to draw new players.
For me, I have enjoyed the game so far. The near constant leveling and loot collecting are fun. I find the game to be very easy on the normal mode, being able to just hold right mouse on many bosses to defeat them. However, trying the harder difficulties, I found the game to be annoying as enemies health get bigger and they take longer to kill, but they do not require any additional strategy (i.e. I used the same attacks to kill them). If I am mentally fatigued from a stressful day, the simplicity of advancing in Torchlight 2 can be cathartic. In my mind, the game fails to be anything more though. All the thinking is in which loot to wear and skills to use, but once you're set up, the actual gameplay is stupidly simple and the story is a throw-away.
In summary, Torchlight 2 is a known quantity. Since there is nothing really new or drastically different, it is near impossible that Runic will offend any of the series fans. On the other hand, it also is impossible that this game will impress anyone who cared less for Torchlight/Diablo/etc. Torchlight 2 is not ambitious, innovative, or inspiring. It is however, consistent, reliable, and safe. It it not the type of game for a hot fling, but one many people could happily be married to for quite a long time. Your enjoyment will vary based on which type of game you're looking for.