I understand why people prefer 2, but to me this is the definitive Borderlands experience. The best map and gun variety in the series, and (my opinion) a more engaging story.
The only thing I strongly disliked was the design of the Sanctuary ship. It took way longer than it should have to get used to the layout and dicking around on board between arcs of the story frequently felt like a waste of time. Characters are still good though and it was nice to see some interplay between them.