It has a very satisfying ending, yes. It was a character-driven show, thriving on mysteries. The writers didn't lost sight of that. The last season delivers the most pressing answers to the mysteries, yet avoid most of the traps (giving answers when they shouldn't have, à la 'midichlorians' fiasco) and the more the end gets near, the more the show returns to its roots as a character-driven show, and in the end it wraps the human aspects in a very satisfying way.

If the beginning of the series is your cup of tea, then by all means watch the rest. On DVD, the few weaker parts pass really fast, and the better parts have even more impact than on the weekly basis.

The show has managed to combine the traditional "human/family drama" type of series with the tradition of shows like Twin Peaks, the Prisoner etc. and in the end they deliver satisfyingly on both counts. It's also like a triumph of the geek. It's one of the most geeky "mainstream" show ever done (and one of the best/most intelligent), yet it has managed to draw in a huge general audience from the start, keep it to the end and satisfy it.