I'm in Hamble Yacht Services, nice friendly bunch. I found them to be a low cost no frills operation that suit my needs just fine. They hosedown you boat, refit your cover and restack - leave a spare set of keys with Security if you ever forget yours.
Good cafe, handy for the chandlers (Aladdins Cave), a stroll to the pubs - but petrol is £1.37 on the fuel berth.....
On balance I'd say 8/10, pontoon access is a bit of a ball ache (slippy ladders, no ramps)
Hope this helps....