Over the years there have been some better than others - and the lead has changed from time to time. I have no idea which one is currently in the lead.
AFAIK all the makers have updated their machines to address known issues and I would expect any brand's current model to be better than past models.
Past issues have included the length of time from pushing the button to dumping the charge of powder in the case - it has sometimes with some models and some powders and some charge weights taken the machine quite a while to arrive at the set charge weight in the pan as the pan fills very slowly with very small amounts of powder trickled into the pan to avoid overshooting.
Taken as a sort of powered powder trickler machines have sometimes gone from undershooting the desired powder weight to overshooting the desired powder weight without ever hitting the exact powder weight.
Folks have even been known to run two machines used alternately to keep up with the rest of the reloading process. I gather but do not know that current machines are programmed better to start with a faster drop and slow down approaching the final weight.
AFAIK all the current machines live up to the maker's claims.
My own inclination is to use a Quick Measure for larger amounts of stick powder, a Harrell's for small amounts, a Hornady or an RCBS (with micrometer setting pistol and rifle inserts) for progressive loading or easy to meter loads with short cut or ball or spherical powders and a Little Dandy for small loads - with a roll of quarters or a socket or other weight on the powder column.
If I had the money to have about three automated machines on the bench for speedy processing that's what I'd have.
