What I like to see, personally, is:-
PNF:- "Positive climb" (or "Positive rate")
PF:- "Gear up"
PNF:- "Gear up selected"
Later, in the after takeoff checks:-
PNF:- "Gear is up (and off), lights out"
The need for the verbal verification is (partly) so the CVR has a record of what is done on the Flight Deck, but mainly so the PF has confirmation of what is being done over the other side, is "in trhe loop" if his attention is all on the instruments. For the same reason, I place strong emphasis on PNF confirming "After Takeoff Checks complete" or "Approach Checks complete, Finals Checks next" or similar.