Advice on Purchasing an HP

[KF6GPE]

I'd echo the suggestion of an HP48 if you can get one. I have both a 28 and a 48. The hinge on the 28 is an amazing bit of engineering, but is also another failure point. My 48 has worked flawlessly since I picked it up halfway through my university days.

And yeah, if you want new- and RPN, the Swiss Micros DM42 can't be beat. The DM41 is a lot of fun, too, and slightly smaller (also RPN). One nice thing about the various Swiss Micros machines is you can easily get stuff on and off of them via USB. If you get a '48, you have to mess with USB to serial and get a special cable if you want to copy anything on or off of it.

Regardless, have fun! Amazing machines.