It's my favorite television show. It's going to get harder to directly sell with the new season though.
So the first two seasons are something like a mixture between a parody of a soap opera with quirky characters, a murder mystery at the heart of it, surreal horror moments, and an off-beat sense of humor. The first season I think gets the strongest with the 'crime investigation' feel of the show, Season 2 ups the surreal horror and comedy elements, then the killer is revealed and after that the show gets almost cartoonishly comedic and kind of unfocused, until it finds its focus near the end and then has one hell of a finale.
Season 3 is currently airing and the first four episodes released less than a week ago still (with 14 more to come), but my opinion so far is that it dropped the soap opera element and has become more like some concoction of Lynch's other films, but I am absolutely in love with the new season so far. It's elevating what was already my favorite TV show, but it certainly won't be for everyone and even some people who liked the original seasons may not like Twin Peaks (reversely, people who liked Lynch's other films and were never big on Twin Peaks may love the third season).
Why I love it would be a bit hard to explain, but I love the quirky characters, the surreal strangeness of the showI find things in the show absolutely hilarious, I love the setting(s), I love the sort of horror it deals with which is very atypical to about any other work that isn't Lynch's, the small observations and odd connections things have, and on a deeper level I just love the scene by scene occurrences in the show.