In general I believe that you are better off seeing an independent. Spring and early Summer are great times to see visiting ladies. They flock to Boston this time of year. Take advantage while you can. January and February to the contrary are quite rough around here. Tough to get a Florida girl up here that time of year. They freeze their little booty and pussy off. Good luck.
Here is a link to the reviews of Boston Agencies on TER. It has their percentage rating of positive feedback along with the number of reviews written, and if you click on the listing, you can read all of the reviews.
The listing have been compiled over the years so a lot of the services on there have been closed. If you find one with good reviews that interest you, then you should click on the website to make sure they are still around.
The Belladonna is listed but they seem to have recently gone out of business.
Guys, incase a lot of you did not know, you can also review agencies in this section as well as the regular section for the ladies.