I use a beam scale for back up myself.
I had the RCBS 505 and it worked well but seemed light and a little rickety. I used a big Ohaus triple beam at work for years so I have personal standards.
Sold it and got a Redding cast iron scale. The Redding is nice and solid but I do have one complaint. It tends to walk around on the bench. Since one of the legs is adjusted to zero the scale, any time it walks around the zero is likely to change.
I find myself bumping into the scale and having to check zero.
Toyed with the idea of drilling shallow holes for the legs to sit in so it can't move. I will do it eventually. Other than that, I prefer the Redding by far.
"If someone has a gun and is trying to kill you, it would be reasonable to shoot back with your own gun." The Dalai Llama (5/15/01, The Seattle Times)
"That rifle on the wall of the labourer's cottage or working class flat is the symbol of democracy. It is our job to see that it stays there." George Orwell