Paid PCalc owner here, never even heard of CalcBot. User of an HP 15c since 1989 (still works) and HP 48GX since 1990 (still works and I also still program in Kermit), I live in RPN and a numerical stack, and appreciate the ability to print out results from either my 48GX or PCalc on iOS or macOS. PCalc is on all 3 of my Macs, it's the first non-Apple app I installed on my new iMac Pro.