I have and use both. If i happen to have a modified case for whatever cartridge im working with at the time, I use the Hornady tool otherwise ill use the Sinclair tool. Also anyone can make a “modified case” with some basic tools.Time after time, people are congregating around this idea they need to use the Hornady OAL tool and then struggle to find a modified case.
Why is nobody using the Sinclair overall length tool?
It’s a one time purchase and will work with any caliber out there.
Ultimately it doesnt matter who uses what as long as it works for them. No need to spend time worrying about it.