I enjoyed playing Decent 3, but like most of the people I know, we still enjoy the first 2 more.
If have never played Decent 1 or 2, then 3 is a good start.
The game play is the same, and the graphics are also better. Just doesn't "feel" the same as the others.
Decent 3, for me, is good on it's own but still a good addition to the series.