Tom,
I've only bought one electronic scale, from RCBS. It is their Chargemaster 1500 scale. I didn't buy others because this one has worked like it should. They typically retail a bit under $200. They can be configured with an add on unit for dispensing powder too. So I guess you could say they are upgradable.
Mine works well. It doesn't drift off zero. I have a set of RCBS check weights and I'll use them at the beginning of my session and at the end....just like I would do for a balance scale. Just a couple of buttons for normal use. It comes with its own calibration weights which I use about 2 or 3 times a year (takes less than a minute to calibrate it).
I'm sure there are others out there that could work just as well. Never had a chance to discover them since I stopped looking after getting the RCBS. I've been using their equipment since the '70s so for me, it made sense to try their scale when I decided to get one.
Good luck on what ever you decide.