I've tried both but prefer the PSR800 over the HP-1... of course, different people have different reasons for liking one over the other -- my feeling is that if you want a radio that layers some additional features and "fancy-ness" over the purpose of the radio - and that is to listen - then maybe you want an HP-1. But if you want to listen - then GRE is the radio you want.
Sure - the HP-1 will let you program using GPS or by entering a Zip Code - but from what I experienced during my HP-1 "test drive", this sounded better than it actually worked. For example, I entered central downtown Baltimore as a Zip Code and gave it a range of at or nearly 0 miles to limit the programming that was enabled. Even then, it included systems like Pennsylvania State Turnpike and systems in Northern Virginia! I also found that some "shared" channels like mutual aid fire, etc. were programmed against all systems verses common objects (GRE!) so when I locked a frequency out on a given system, it would pop up on the next system and I'd have to lock it out there too (kinda like "whack a mole").
With the PSR800, you pick what you want to hear and you can customize the programming too.
The audio is much better on the PSR800 and it's much more portable.
My BC396 is functioning as a pager at this point and my PSR500 is a backup to my PSR800.
You decide.