As above, unless you want to measure something else the RCBS is about as convenient as it gets. I have had very good luck with mine but also have the Stoney Point attachment. While it does do most cartridges, which is why I bought it, it works best or is easiest if you have a go gauge to set it to zero with. It's also important to remember that the SP is only as good as the 6 inch caliper you attach it to. I would go broke buying RCBS Case Mic's for everything I reload.