Probably the best Facebook chat application i come across to replace the native FB Chat.
• Easy & Secure Facebook chat login
• Nice UI
• Facebook groups
• Favorites notifications
• Friend alias
• Share images and location
• Send video, photos and voice notes over Facebook chat
• Swap conversations with gestures
• Homescreen Widget
• Access Facebook profile right from Facebook website or Facebook official app
• Send messages even when the other contact turns offline. Messages will be delivered through Facebook chat as soon as he/she comes back online!