The only thing I don't like about the RCBS spring scale is that I seem to get quite a bit of variability with repeated measures on the same trigger. Maybe it's how I'm using it, but the average of the measurements seems to be close to specs. So I guess it serves its purpose.
That may be your rifle trigger or the way you are using it. When I check trigger pull, all of mine are very consistent. if not, they need some work.
I use mine with every new rifle I get, when I'm fine tuning a trigger, or changing parts. Doesn't get much simpler than the RCBS unit. Been using one for many years..