I’m another than watched the whole run this year (with my 12-year-old girl) and enjoyed it thoroughly. And I take a back seat to no one as a fanboy.
Dude.
Jolene Blalock in wet and tight underwear in a ‘decontamination room” sequence..
All you need to know.
But other than that? Meh.
Ironically, after the events in the latest movie, Enterprise is the only TV series that is part of the new canon. (Everything else takes place in the universe where Vulcan is still a planet.)
The Abrams movie doesn’t invalidate the original series or any of its sequels. It’s an alternate universe, not a reboot.
Enterprise is okay at points, but not really that good overall. In my opinion, the only Trek that has really stood up well in retrospect is DS9 and some of TNG.
I’m a big trekkie fan, even watched all of Voyager. So with that in mind…
Yes it is worth watching, it is overall better than Voyager. The first part of the first season is very good but then there is a long lull where most episodes are very MEH, until the third and fourth season where things really get amazing with tons of call backs to TOS like seeing the augments and Orion “slave” girls. The series finale is one of the worst things I’ve ever seen however, and might invalidate the whole show.
I also loved the prominence of the Andorians :).
I’d watch the first season or the fourth, check out the rest if you like it.
It had just started to reach its potential in the fourth season, then blammo - cancelled.
The last episode of the series should be skipped, but saying it “might invalidate the whole show” is completely overboard. There was a slightly-similar concept floated for ending DS9 that I thought would have been pretty great (and, in fact, would have made a respectable ending for the Trek chronology as a whole)–
The view of the galaxy at the end of “What You Leave Behind” fades to black… then lights up with the face of Benny Russell at his typewriter. He taps the final period, smiles, and yanks out the last page of the manuscript.
With alternate universes both are still canon. For that matter, with time travel changing the past contradictory episodes set in the same universe can still be canon. Sort of.
Here’s a list of episodes to watch from the first two seasons–basically the list I wish I’d had. These are the ones that (IMO) work best with the placement of the series as a prequel to the rest of Trek, especially the human-Vulcan relationship, or are highest-quality in themselves, and avoid the worst blunders of the series.
“Broken Bow”
“Fight or Flight”
“The Andorian Incident”
“Breaking the Ice”
“Fortunate Son”
“Silent Enemy”
“Shuttlepod One”
“Fusion”
“Vox Sola”
“Fallen Hero”
“Carbon Creek”
“Minefield”
“Dead Stop”
“The Seventh”
“The Communicator”
“Vanishing Point”
“Dawn”
“Stigma”
“Cease Fire”
“Judgment”
“Horizon”
“The Breach”
“Cogenitor”
“Regeneration”
“First Flight” - the main story of this one is a prequel to the prequel-series, so you could actually watch it first, or at any point
No doubt somebody will quibble about including or excluding this or that episode, but for the most part I think you’re better off being selective.
First two seasons are hit or miss. The third season was a pretty good sci fi show but not Star Trek. The Fourth season is when they finally embraced the Original series whole heartedly (although every season used references is some ways, sometimes subtle, sometimes not).
That’s when they approached Fan Fic. It was the very best, and the very worst.
And, dammit.
Serious spoiler follows.
They killed Trip! The bastards!
Yep. If I continued the list above, I’d skip almost all of the third season (except the alternate-reality “Twilight”), and its ‘conclusion’ in the first three of the fourth.
Well for me it made me question whether what we saw was real or just a flawed and of questionable accuracy creation of the far future. I wondered if they did that to stop canon complaints, hey guys if you notice a canon incongruity a wiz..er holodeck did it!
It just seemed disrespectful to pull that crap in the last episode, I remember some of the cast even disowning it.
EDIT:Forgot to mention Enterprise had one of the best mirror universe(evil Spock with a goatee) episodes of all the series, it also explained something from TOS which was cool. But man I hated the redesigned Gorn.
Which is a very Trekkie way of looking at it.
Just watch some of it. If you can’t stand cynical Vulcans and Andorians, and Terrans trying to figure out their way in a pre-Federation setting, or if any little contradiction of your headcanon drives you up the wall, then Enterprise may not be for you.
But if you’re that guy, a *lot *of fiction is going to annoy you.
I really like the Andorians in this. And the Vulcans are pretty much what Vulcans are, which is to say, not the idealized image that a Romulan might have of Vulcans. 
I watched maybe two seasons, and couldn’t get into it. There were way too many poorly-written time travel episodes.
The episodes set in the evil alternate universe are pretty fun. Scott Bakula foaming at the mouth as a rage filled mutinous space Nazi is just plain good TV. Other than that, it’s not so great. And some of it is down right awful. But then again, only about half of TNG is worth watching, and I hated Voyager, so you might want to check out a couple of the better episodes if you really liked other forms of Star Trek.
None of it approaches the best of trek, but it’s usually better than the worst episodes of any of the other series. It’s a been a while, so I don’t remember which ones are worse.
I do know that, if you want to watch the finale, watch it now to get it out of the way, as it is so disappointing later. It’s easier to discard if it’s not the last thing you see.
And every word he spoke sounded like he was quoting from the bible.
I liked it well enough, and for what it’s worth, here’s a site with episode reviews that was recommended to me when I did a re-watch some time back, and found generally a very useful guide.
I also think it’s a shame it was cancelled right when it seemed to find its stride… Also, I would’ve loved to see this refit design in action (provided they’d actually gone with it). I nicely interpolates the evolution toward Kirk’s enterprise…