I haven't used them from Vermont, but I fly them all the time from Philly and Trenton to Orlando and Myrtle Beach. They are my preferred airline and I haven't had any issues that would be unique to them. One bad delay out of 6 round trip flights this year (and so far only one in the past 4 years) and without any questions they sent everyone a food voucher and then a $75 flight voucher so I got another free flight out of it. Prices can't be beat, but you have to know the pricing structure up front and use it to your advantage.
I personally like that they charge for bags separately because I rarely need checked bags or even carry on. I'm good with the free personal item under the seat for most trips. Sometimes I pay to choose a seat but mostly I don't. Never had an issue there even when traveling with all 5 of us. Seats don't recline unless you pay for the few areas they do, but for a 2 hour flight it's not an issue to me.
They are one of the only airlines I know of that has an emergency cancellation policy. I had to use it 2 years ago and it was awesome. Flights have been good, most of the time we land a tad early. Flight attendants have been great.
All in all I always highly recommend them and will continue to use them. The only reason I fly a half dozen times a year now is because of the amazing rates I get on Frontier.