Is this actually worth watching?

Wondering the same myself...but huge disclaimer: I HATED the prequel films. Always assumed I'd hate this too, since it's based off Lucas' worst work.

It gets really dark in the later seasons, it shows the negative side of the Jedi Council and shows you that Anakin's change to the Sith was not as quick and immediate as it appeared in Episode III. Plus you'll get to see Darth Maul return, Boba Fett try to avenge his father's death, and pretty much get backstory on most of the minor characters in the prequels.

Definitely worth a watch.

I think it's very good as long as you follow it chronologically, that's one thing I feel hurts Seasons 1-2 and the first half of 3, the DVDs and netflix have the jumbled air-date order. Granted Season 2's "Cat and Mouse" isn't the best beginning compared to the feature, but it does show a decent starting point still early in the wars as Anakin is settling into the mantle of Jedi Knight and developing a respect for the clones. There are some things the 3D series skips past (Anakin's actual Knighthood, 3PO's gold upgrade, introducing Grevious and Ventress) or doesn't quite get to (the Separatists invading the outer-rims, Palpatine's abduction, why Grevious coughs much more) that the 2D cartoon covered. But once you get through the Clone Wars series, rather you choose to watch the 2D micro-series with it or not, it really does feel like you've lived that three year war with the Jedi which Attack of the Clones' opening salvo and Revenge of the Sith's concluding conflicts glimpse.

If you'd like an ideal chronological order I can give you one.

Superman & The [Red-Blue] Blur = The Man of Steel

It starts off pretty weak and childish, like they weren't sure what kind of show they wanted to make, but it ends up being pretty solid (and a little dark).

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WORDS MEAN THINGS! Also, before you come to bitch about a plot hole, rewatch the show/movie.

Like you, I'm way out of the age range of this series (it's made by Disney for Disney TV unlike the new movies, which I've enjoyed). Season 1 is TERRIBLE and adds little or nothing to the plot or lore of Star Wars. Starting from Season 2, however, things start to get interesting and the show becomes a bit darker and truer to the films, and also begins to more substantially expand on the lore. If you can force yourself through season 1, you'll be rewarded.

Things that will likely turn you off:
-Battle droids pretty much have the personality of Jar Jar Binks for some reason, and you'll be hearing A LOT from them. This does NOT stop, though they admittedly did make me chuckle on occasion.
-A few standalone, Jar Jar-centric episodes bog down the series. They even mention him getting trained, but he ends up still sucking and still annoying as ever.
-Highly episodic stories all-round as opposed to a single continuing arc, which is fine, except that a lot of them are very sub-par and forgettable (i.e. most of season 1). They do get much better as the show goes on.
-Mega-cheesy narrator voice-over instead of a text crawl (likely due to run-time, which I suppose can't be helped)

Things you'll likely enjoy:
-Slightly more background on characters, from Obi-Wan and Anakin down to the less-seen Jedi in the movies. Obi-Wan in particular, you get to find out more about his life.
-Ahsoka is less annoying than in the Clone Wars animated movie and eventually grows to become a better-rounded, much more interesting character.
-Cool space battles and action scenes (lots of death too, for a Disney show).
-Clone characters are very likable (which in a way is disappointing, since most end up turning on the Jedi in the movies) and bring up interesting dynamics as to the morality of their participation in the war, which was essentially forced on them.
-Certain elements from EU make a comeback in some form or other (Mandalorian War, Darth Bane, Ventress, Quinlan Vos).

It's amazing. It's actually become my favourite thing of all Star Wars. The movies, the books, the comics, the games, this is the good stuff.