Both Sunbird and Beeper is leading the pack with this method and kudos for them giving Android users the ability to use iMessage without the need for additional hardware, but I prefer using BlueBubbles.
I've used AirMessage in the past and one thing that always annoyed me was the lack of read receipts support... because when I'm using my Mac or iPad, I'll have tons of notifications/badge alerts on those devices. And I personally don't like having too many notifications or alerts, but I can understand completely that most people don't really care about that.
Most people are just excited with having iMessage on Android (regardless of certain features missing) given Apple reluctance to make it cross-platform.