I don't need iMessages mainly because most of my contacts don't use it. I used to enjoy WhatsApp. For MMS, it is one of the best out there. Except it doesn't do voice calls like Viber.
For MMS or long distance call, I use Viber. Or my parents just call me since they have Vonage. For free text messages, I use the Google Voice app or its mobile site. I really do miss using Talkatone for voice calls. I tried using Hangouts the other day and its dialer for VOIP, I still get confused.
I can never go back using iOS. It is longer to enjoy Android if you customize and use the apps below -
Nova Prime and its many launchers
All In One Gestures
DynamicNotifications, AcDisplay, Floatify, CM Locker, etc
Wakeup Touch Nexus
Screen Off & Lock
Notification Toggle
Lazy Swipe
QuickPic
MoboPlayer or MX Player
UberMusic w/ Metro UI skin