Have lived in both places:
Halifax advantage:
Housing is somewhat more affordable;
The Navy is bigger (= more people to do the jobs required);
You are not on an island;
Lots of outdoor things to do;
People are very friendly; and
Great Ports (NY, Boston, Carib, Europe).
Halifax disadvantage:
Winter weather is crappy (snow and rain); and
No Sunday shopping but you can get hammered and lose your shirt gambling.
Esquimalt advantage:
Winter weather is somewhat nice (you do get some snow, but the rain can make you go nuts);
Not too many insects (they grow in size and number the higher in elevation you go); and
Lots of outdoor things to do; and
Great ports (SF, SD, Seattle, Portland, South America, Mexico, NZ, Australia, Singapore, Pearl).
Esquimalt disadvantage:
Price of housing (PLD going up though);
Traffic is getting Vancouver like;
BC Ferries;
People are cold;
Tree huggers galore; and
Did I mention that you live on an island?