Pros: Ergonomic. Good keypad (proper spacing between keys is increasingly rare, it makes dialling so much easier). The stand has a shallow recess that the phone sits in, so it doesn't fall off its perch at the slightest knock. Great sound quality. Excellent battery life. Very effective speakerphone. Shared phonebook. Takes standard AAA NiMH batteries, so it won't cost much to fix when it no longer holds a charge.
Cons: No SMS. Slightly basic-feeling user interface, in common with some other Panasonic products.
For me the pros outweigh the cons. I bought these after returning some disappointing BT Verve 450 handsets. They looked great and had lots of neat features, but I felt they were flimsy, and they had poor audio quality. What Panasonic give you is the basics done well.