So 3ft difference between a $400 handheld unit and a $20 phone application? Not too shabby. However one thing I do not like about the phone apps is the battery life. Less then 2 hours in my situation. Im actually debating getting a new phone or the PN-40. I purchased a Magellan 4000XL for $399 about 10-15 years ago. The cover on one button is ripped but still works great. Ide purchase the PN-40 for the simple fact 2AAs can run 18 hours, and I have 16 rechargeable AAs for the current gps unit, which takes 4 AAs, and my Fendix LD20 light perfect for night geocaching (also 2 AAs).
I guess the point im making is, if your serious about caching, and you dont have an expensive micro laptop phone already, its going to cost a few hundred for a good unit with awesome features either way you go.
I get several hour on my Curve. Havent completely run in down yet, but i have gotten over 4 hours.