I settled on City Life Wellington as having the best mix of location, rooms and price during 9 months of weekly trips and trialing several CBD hotel options.
Great location on foot or driving near the motorway. Very well appointed rooms and the biggest plus for me was proper kitchenette facilities, much better than most standard hotels which for me made it great value.
Friendly staff and fairly well equipped gym.
The only downside is no restaurant (including breakfast) facilities, although this may change again in the future. Plenty of options right out the door though so this shouldn't put you off.