basically there's no significant difference,
SLCD is better in displaying text, the text appears to be more crisp and clear on SLCD,
while AMOLED is more vibrant on colors, having higher contrast compared to SLCD,
SLCD save more battery compared to AMOLED when displaying full white,
while AMOLED save more battery compared to SLCD when displaying full black,
however, those difference are really minor, not worth the worry.

WF froyo changelogs:

The most notable are:

    - Support for USB tethering
    - Possibility of installing applications to SD card (if supported by the application)
    - Native support for Activesync Exchange (email, contacts and calendar sync) and security policies
    - Enhanced Camera application
    - Enhanced Bluetooth support
    - Speed and stability improvements
    - Multiple keyboard languages
    - WiFi Hotspot tethering

    NOTE: “Live wallpapers” and “Flash” support in the browser (Froyo features) are not supported due to hardware limitations.

Not support live wallpaper??????? time to change hehe3x