I used to live in Boston and am now in Portsmouth NH. The towns are entirely different, and where you should live will depend on a number of factors. Here are some pluses and minuses for both towns.
Boston pluses:
-everything a large city has to offer
-so many bars/restaurants you will never see them all
-job market is quite good, relative to surrounding areas
-Lots oftouristy and non-touristy attractions
-MIT, Harvard and BU are within 5 miles of the city, meaning that there will be a lot of young men/women (whatever you are into) to chase if you are single.
-Easy egress from the city via train or plane. NYC only a 4 hour train ride away.
Boston Negatives:
-property values are sky high. Condos in the city go for ~$500/sq ft
-Traffic sucks.
-The people are fairly isolationist. Don't expect random niceties or people to engage you in conversation in a store.
-Just about everything is expensive. Food, gas, parking, etc.
-Oddly, it was fairly hard to find a general practitioner that was accpeting new patients when I was theere. There is an undersupply of GP's in Boston.
-income tax
-State government is run by a bunch of idiots.
Portsmouth positives:
-just about everything you need (with limited exceptions) is only a 5 minute walk or drive away
-Property values are ~45% of what you will see in Boston, provided that you are not looking within .5 miles of downtown Portsmouth. Once you enter downtown, all bets are off.
-0 traffic
-Beaches are ~10 minute drive away
-Skiing is ~1 hour drive away
-downtown area is reminiscent of old town alexandria (a very good thing)
-plenty of good restaurants
-people are very nice. Within 2 weeks of being here I knew most everyone at the local coffee shop and grocery store I go to by name.
-5-10 bars available (quite a bit for a small town), and the music hall provides some culture
-no income tax
Portsmouth negatives:
-Job market is quite small (might have to move if you lose your job)
-Town is small enough that one could get bored easily
-Parking is a pain in the winter if you live in town
-Rents can be high
-the average age of the housing in the area is ~100-150 years. Everything is old, and a lot of propoerties show their age.
-Sprin/Summer/Fall are even shorter than they are in Boston.
-high meal tax
-schools are funded largely by individual towns, as opposed to by the state. Not really an issue in Portsmouth, but cold be a concern if you want to move to one of the surrounding towns (Stratham, Rey, Greenland, etc.).
Personally, my vote is for Portsmouth if you can swing it. But as you can see from the above, Boston and Portsmouth are entirely different towns.