I'm not sure I'd say the i700 is better than the iPAQ 6315, but certainly different since they're on two different networks running CDMA and GSM respectively.
You will get faster data speeds on the i700 thanks to Verizon''s 1xRTT network. The Samsung has a faster processor, but the iPAQ has Bluetooth and WiFi built in, so they each have their charms. Both are worth considering, and though the i700 is older, it still offers a great deal of current and desireable features.
Neither have native support for landscape mode. You'd need to check out third party screen rotation software.