If you want to get out and see some interesting Boston sights, then pick Boston.

Companions most frequently stay in Waltham but there you're basically stuck to your room. There are few restaurant options around but usually are very few.  

It's much more fun to stay in Boston or Cambridge. I think more companions stay in Boston than Cambridge.

Yours is a fairly frequent Q. Here is one thread from ~2 years ago that discusses pros and cons.
http://www.theeroticreview.com/discussion-boards/boston-9/a-few-qs-and-then-suggestions--and-a-boston-neighborhood-map-226278
.
It also includes the suggestion to split your visiting time between downtown and one of the 'burbs. See which YOU like for different reasons: (a) biz reasons - which location is more successful for you (b) personal reasons - tourist-y stuff: museums, clubs, restaurants, shows, ... .  
.
Use the search function to find more threads on the Boston board about the same topic.
.
Have a good trip! Good luck!

…way cheaper hotel rooms. Little to none of the bullshit with elevator key cards like in the city and tourist areas. Easy parking and less crowded lobbies and common areas, so fewer probing, questioning eyes. Burlington, Woburn, Lexington, Waltham. Boston is a pain in the ass to navigate, and it will only worsen as we head into better weather, college graduations, etc.

Both are “close in,” “city” options that seem to be fairly accessible to anyone staying or working in the central city area. I’m staying in Cambridge when I tour next month because that was the best balance of location and hotel price points for me.

I don’t think it’s a major difference like Boston vs Waltham.