well if it is your first con furfright would be a good one to go to

Midwest furfest is the best.

For worst I been to a few bad ones so not sure which is the worst.

Since you live in Maine, the best ones for your would be:
FurFright (FF) in Cromwell, CT - Happens Mid-October
Furry Weekend Atlanta (FWA) in Atlanta, GA - Happens Mar 15-18 - Moulin Rouge Theme this year
FA: United (FA:U) in Whippany, NJ - Happens August 17-19 - GTA Theme
Anthrocon (AC) in Pittsburg, PA - Happens June 14-17 - Midsummer's Night Dream

These are the ones that have been recommended to be by East coasters. I've been to AC and FF and I love them! Both of very cost efficient especially if you drive yourself down there and room with friends.