DM42 early units vs. current?

[lrdheat]

Thinking more about my experience, my DM 42 purchase, inspired by my HP-42S, still is problematic concerning key presses registering when hand held. It is much more reliable when on a hard, substantial surface such as a desk. The HP 42S is a joy to use hand held or on a desktop. The HP 42S is my shirt pocket gem.