Why is uploading sketches slower when using EZ-Link than using a USB cable?
Wireless just isn't as fast as wired. For example, with USB 'wired' data, the data is just 'sent' because the wire is trusted. With wireless/bluetooth, there has to be a lot more layers of checking and verification because there's no way to know if it was received and its suscepitble to noise. You can try to speed up by unchecking the Verify Firmware box in the Prefs of the Arduino IDE, that should cut it in half...but of course adds some risk!
I'm using Windows and unable to pair/connect to the Serial Port and/or the EZ-Link pairs but I cannot actually use it to send/receive data!
Make sure you do not have any extra Bluetooth drivers installed. In particular, make sure you don't have CSR/Harmony bluetooth drivers or any other non-Windows-native bluetooth stack. You should be using ONLY the native Windows bluetooth! Unpair the EZ-Link, uninstall any other drivers and reboot, then re-pair. For more details check out this forum thread:
It this Bluetooth Low Energy?
Nope! BLE is not supported on Windows 7, so we use Bluetooth Classic which is much more universal. In particular, this is a Bluetooth classic 2.0 - Class 2