I have the Trend one from the OP and to be honest it is quite good. I haven't removed the batteries since purchase around February and it worked fine yesterday
I use it to set up things on the mill and any shelving too. As above, you zero out a reference surface and then the degrees are relative to that.
Very handy!
same, never removed the batteries and never had a problem.
readings are repeatable so i believe it's accurate to what is says it is