I notice that we tend to have similiar opinions about things so I thought I might recommend giving ENT a chance in season three and four. I really felt that both were entertaining. Season three was a vast improvement over the first two seasons and if you like story arcs this one is pretty good. It adopts a Lost/Heroes format to some degree throwing a bunch of unanswered questions at you, has a pretty impressive storytelling canvas, the mysteries are engaging, and there is plenty of excitement and suspense.Enterprise is the only Trek series I found unwatchable. It comprehensively failed my primary criterion for liking any TV show: Namely, interesting characters. In all honesty the only Enterprise character I found even remotely interesting was Porthos, and when the most interesting character in a show is (literally) a dog it's not a good thing. If I can't get interested in the characters in a show, I couldn't care less about what they do. And what they did didn't interest me much anyway. It was generic, formulaic and bland.
To each their own, but the show wasn't for me and thus I stopped watching.
And since you don't care for the characters too much, the season is mostly plot-driven where we see the characters trying to get to the bottom of everything. It does a good job in respecting continuity, developing a rather impressive mythology for the aliens and the region of space they inhabit. And despite knowing the outcome the show imparts a great deal of peril into the unfolding events. Even Archer and T'Pol have some nice character work.
I must point out though that the season is not nearly as consistent as Lost or Heroes. It is quite erratic. When it focuses on the arc threads the episodes are mostly good , great or even excellent. When they create a standalone with no real connection to the arcs they are rather middling but I think in the end it was worth sticking it out because I really enjoyed myself.
And if you like TOS, I think you'll enjoy and appreciate season four. I thought it was the most consistent season of the series. It wasn't perfect but I thought the writers did a good job of telling a series of stories that not only stand well on their own for the uninitiated but also added some richness to the Trek backstory. The stories, with maybe one exception, didn't exist to serve the namedropping or fan elements but rather used those pre-existing Trek pieces to enhance the episodes.
Once again I think many could enjoy this without liking the characters because it really was more about looking into the TOS aliens, their relationships, their culture etc. Usually the stars of the show this season is Archer and the guest of the week.
So I just thought I would throw that out.