Unfortunately I live outside 495. Shared Van from the Worcester area is about a $100 round trip, so only really worth it if you are going for a long trip or are traveling as a group (additional passengers re much cheaper). My biggest problem with Logan Express is that the current temp parking lot is not very secure and that to get there you have to navigate the stupid traffic around the mall. Poor location choice. Plus, on weekends (when I travel) the bus only runs hourly, which adds more time to getting to the airport. I usually find that unless I am flying cross country I spend more time getting to and from the airport than I spend flying.
I have always wondered why there is no bus service from Worcester. I suppose I would be a little more accepting of the parking fee increases if they didn't then make you pay a full additional day when you go on a two night trip and arrive a few hours later than you took off.