Connectivity, Battery and storage
The HTC Butterfly comes with micro-USB, Infrared, WiFi, Bluetooth 4.0, and NFC. The micro USB port also can be used as HDMI port but for that you have to get a special cable. Infrared is a good inclusion which can be used to convert the phone into remote control for various home entertainment systems like TV and Music system by merely downloading the relevant application. The phone also has GPS + GLONASS (Russian global position system) for better mapping function.
The HTC Butterfly has a 2020 mAH battery which in itself doesn't sound great for a device of this size, however it will depend on how much power management helps in deriving maximum back from this unit.
In terms of storage, the phone has 16 GB of memory and thankfully there is also a micro SD card for up to 32 GB.
Conclusion
The HTC Butterfly is big yet slim. Also, not only it has great looks but provides superb performance too.