In most cases climb like hell until the final 1000'
I thought most company sops say to reduce to 800'per min for the last 1000 for tcas. Most good controllers will be expecting this if assigning you rate, but if in doubt ASK! The controller will issue maintain rate until lvl or something similar if they are running it tight and need you to keep the rate until you are at lvl.
The best acft for us are the 737-600. The climb and decent portion of the flight is always the most difficult to control due to the changing condition- wind directions, speed, rates of climb/decent and most of all traffic complexities. The sooner we have you at cruise the better it is.
Also, if assigned a rate, it is not an average. For example we may issue a rate of 1500 for your climb from FL300 to 380. It is possible there is multiple restrictions for your climb, so for the first 4000' feet if you only climb at 1000, and the last 4000 you climb with 2000, the average rate is 1500. But for the first 4000' you are under the profile and therefore will be lower than required to possibly avoid the traffic at FL330. If that doesn't make sense, draw it on some paper.
Happy flying