I live in a townhouse, and have done for 12 years, since DD was 3. We like it.
Only issue we have had is:
(1) not all window cleaners are able to access the top floor; round here a couple actually highlight they can clean townhouses in their advertising; and
(2) getting a sky dish was trickier when we moved in as Sky themselves wouldn't do it. However a quick phone call to a local TV aerial company sorted in the next day - tall aerial and sky dish attached to that.
As with many places, a lot may depend on layout.
We made some changes to ours a couple of years ago when we added an extension.
WAS BEFORE
Ground floor: garage, downstairs toilet, 'garden' room (we used as a playroom, a dining room and a study over the years), utility room
First floor: living/dining room (big L shape), kitchen
Second floor: three bedrooms, one ensuite, family bathroom
NOW, SINCE EXTENSION
Ground floor: good size storage room (was garage, now reduced in size), downstairs toilet with storage cupboard, large utility room, good size open plan kitchen/dining.
First floor: good sized L shape living room, study/snug (could be a 4th bedroom)
Second floor: three bedrooms, one ensuite, family bathroom