Horizon: (I have flown over 50 Horizon segments so far this year)
My likes: Generally friendly employees top to bottom.
Absolutely love the Ala Carte - checking baggage into SEA is the worst.
The adult beverage selection.
Goes where I need to go for the most part.
Dislikes:
Pricey
Frequent flight cancellations/delays (my flight to PDX was canceled this morning)
You run the risk of having some really large passengers next to you whenever you fly. Can get really gross during the summer when everyone is hot and at best - sticky.

An exit row at least takes the belt extension passengers out of the equation.
Not convenient to MT - I almost always have to fly in the night before...
All in all - good regional airline.