I have the lelit PL041em (same machine as pl042em just without the integrated grinder)
I absolutely love it and i really like the pressure guage.
To be honest, i could probably live without it.... but it is handy to see if i am overdosing or underdosing etc.
Is it worth $50?? not sure... but really when you are already spending $800 odd dollars on something does $50 make that big a difference?
Also, i personally preferred the buttons on the EM model, i know it is purely cosmetic, but when you spend that much on something you want to like how it looks!