These are tri-mode phones which are analog at 800 MHz, TDMA digital at 800 MHz and TDMA digital at 1900. Sprint also has analog and digital phones. One frequency is not necessarily better. The difference between the two is how well and extensive the networks are built. The 1900 MHz operators came on much later than the 800 MHz operators and may not have as extensive coverage as 800 MHz operators.
Handset prices range widely.
I understand that with increasing price, you get more features and smaller size. Phones undergo stringent testing before an operator will sell them. If networks are not built out well, then the quality will sound poor. CDMA has a theoretical advantage over TDMA because of its increased congestion tolerance. Code Division Multiple Access.