Keep practicing, you'll get the hang of it.
I use the UMmu on a regular basis to grab a "fuel" container from the DGIV cargo hold and carry it to the nosecone for refueling (to me using the docking autopilot feels like cheating, but that's just me). I EVA, fly back and pick up the turbopack, then head to the cargo bay to get the container and fly it to the nose. Takes a while to get to the pack and also back into the ship after you stow it away, but I think it gives a more realistic feel.
I do however agree that the UMmu itself should have a bit more power in the thrusters.