I used to have PCP's, I've reverted to springers nowadays. Filling from a cylinder is a much more relaxed way of going about it, but using a pump is very practical too.
For rifles with an air tube reservoir it's can be pretty routine, but I've filled a few buddy bottles from empty, & you definitely need to take a deep breath before you do that.
I've never noticed any issues with condensation, but I've always used a DriPac as well as the intrinsic water trap.