I voted for Acting, character development, production values, Jolene, recurring cast, and other; I also voted for supporting regular cast by mistake, but it's not such a bad mistake since Billingsley was great, and Keating was very good, too. But in many cases I need to qualify this with "some of".
e.g.:
Character development - for some of the characters (Archer, T'Pol, Trip), it was as good as on any other show (in terms of actual character growth, second only to DS9); others were short-shifted.
Production values - I should qualify this with "season 3 production values". They were average in seasons 1 and 2, compared to other shows of the 2000s. But in season 3, they obviously re-vamped the show, and the visuals were just amazing (especially in the scenes of Expanse anomalies; battle scenes were also great).
I really couldn't vote for Storylines, because while I really enjoyed some of them (the Vulcan/Andorian/Tellarite relations and the building of the future Federation, the Xindi arc, the Vulcan trilogy, the Romulan involvement, Terra Prime, the Mirror Universe two-parter), many others (particularly many of the standalones, with exceptions such as "Cogenitor") were just lame, dull, derivative drivel that clogged the first couple of seasons, and made ENT look like a safe, unoriginal and inferior retread of earlier Treks. Storylines were really the biggest problem of ENT. But when they got good, the show got good.
Though Connor was really good, and Scott was quite good once he got a handle on Archer, I voted for Jolene because I really enjoyed her performance and T'Pol is my favorite character on the show.
Recurring cast: Soval, Forrest, Shran, Degra, Cutler...
I liked the acting on the show because it was more realistic, low-key and made the characters look down-to-earth, which was a refreshing change - even though I enjoy the larger than life, flamboyant characters of other show, this was one of the things that set ENT apart.
Which brings me to the "other" department.
I really liked that the characters were more similar to 20th/21st century people, more like people you could meet in real life. I liked the 'prequel' feel of having film nights instead of holodeck, or being less 'enlightened', or obviously not having that much experience with space travel.
The single things that most delighted me were:
- the serious way that every redshirt death was treated with
- the amazing visuals in season 3, with the Expanse anomalies being shown in all their glory (in VOY, for instance, anomalies were usually shown by having people talk about it) and having it also matter for the story, unlike being a tired all device as they were on VOY
- the battle scenes in "Azati Prime/Damage", with audacity of showing people being sucked into the space from the wrecked ship;
- having the ship really wrecked and having the consequences felt in the next episode;
- the audacity of having a main character who is, practically, drug-addicted, without getting all judgmental about it
- the alternate opening credits for "In A Mirror, Darkly". Just awesome.
- having a MU story set 100% in the MU, and without a 'happy ending'
).
Sure, maybe there were elements that didn't delight me 100% of the time (Archer needed more consistency, Travis had untapped potential, some goofball plots here and there, etc) but I found delight in each of these categories. There were storylines and performances that blew me away. I loved the look and feel of the show, and the relationships between the characters. 
and I suspect her consort was, too, tho' who knows how long he survived... 
