On powder measures...Most of the major powder dispensers use a rotary action. Since the diameter of the rotor defines and restricts the length of the piston movement (the "stroke" in automotive terms), if you want more of less powder measurement, the only dimension you can play with is the diameter of the piston (or the "bore"). So as shown above the RCBS UniFlow comes with 2 rotors (large bore and small bore). The small bore is required to get accuracy on pistol loads. Large bore is required to get the volume a 30-06 requires.
Both Hornady and RCBS use a nearly identical design involving interchangeable rotors, with slightly different hopper designs. The Hornady is the more evolved of the 2. The RCBS has been around since ~1970 and is a lot easier to find used. Both have available a "case activated" linkage option. The Hornady LNL AP uses this linkage.
On scales.....In the quality of powder measure you are discussing,
you use the scale to set the measure and then use the measure to meter out powder for the next hour or so. So yes, the digital can be faster, but you really only use it when you change the cartridge you're loading. So, if you reload 9mm for 2 hours, then you've really only saved 2 minutes out of 120 minutes. Follow? To most people that's a negligible savings.
Now, on the other hand, if you were going to the Olympics or such and wanted the EXACT powder in each case, then you'd be weighing each load. In that instance your savings would be significant. So it really depends on the type shooting you have planned.
If you really are dead set on a digital powder measure, then jump up to
Jay's Corner and look at the Winstead digital scale our sponsor
Berry Mfg offers for a discount to CZ Forum users.
Click Here That's a fine scale and the only one under $200 I can recommend.
On beam or balance scales, Ohaus makes almost all of them. Even the ones they don't make, like the Redding, they still make the beam part of the scale. If you scan all the scales on Ebay you'll start to see the same design over and over branded several ways. Those are all Ohaus. All the scales Ohaus has a hand in are accurate to within 0.1gr.
I like a scale that reads to 10 on the adjustment bar. If it only reads to 5, then you have to remember the 2.1gr showing is really a 7.1gr weight. No difference in the scale accuracy, but just another bit to file mentally.
Hope this helps.