I've used the D5 some. It's a nice tool to have, but it cannot solve all problems, you can only rarely get readings from bushes and stuff like that, you need a tree trunk or similar. For a bit longer distances you may want to mount it to a tripod too. However, the D5 is much better than older distance meters. The old laser distance meters I did not find to be that usable, too difficult to get readings without a tripod and flat target surface. The D5 has much faster readings and can do them in more difficult situations, making it quite usable handheld. Just don't expect it to give you readings in all possible situations.
Most often I just estimate distances, but it is also something one gets better at after using a distance meter for a while. I focus on the ground glass though, so I don't need the (exact) distance as often as for an RM3Di or Alpa.