RTK is a much different experience than the BG series or Arcanum. Notably the story is much much more personal (you are Squire James, a person with a lot of background, not simply 'a child of Bhaal'). Though, I should say, BG is probably my favorite series. The other big difference is the 3D camera angle, which shifts all around through the game. The game has a number of technical flaws, including strange camera angles and gameplay imbalance (most of the action can be weighted in the first parts of the game). Moreover, the character models are clunky, flat-faced and sharp.
However, RTK has an interesting story, beautiful landscapes, entertaining voice acting and, I thought at least, a very fun combat system. Moreover, the RTK comes with a rich and developed background which is not limited to the small piece presented in game. The loot drops are random on encounters, though there is specifically set loot as well. Additionally, there are a number of small touches or encounters you probably will never find your first time through. These two features make for a surprising amount of replayability. I'm also quite partial to the music.
I think RTK is well worth it. And, though I have the CD, I will eventually get the GOG version just for the convenience and compatibility.
