I have an old Redding #2 bullet scale and a new RCBS 10-10 scales and I believe using gravity is the way to go. I say that because I am always looking for what is the better and the cheapest that will do the job. (Price matters
Now I also believe that the newer electronic scales are very good too. I have looked at and used a few of the cheaper electronic scales and they never weighed the same powder in the same pan twice at the same weight, however I do know loaders who use the more expensive electronic powder measures and they all to a man/woman think they are nice and would not go back to using gravity again. Of course if they can't find batteries or the electricity fails then they may have to change their minds.