Whatsapp is a great BBM Alternative. It shows one checkmark when the message is sent and accepted by the network and 2 check marks when it is delivered to the phone. It does not show read or unread. It does to group chat and you can attach a host of stuff (Pics, video, music, location (cool so friends can find you and get directions from google maps), and contact info. I think it shows if the other person is typing but not sure. My brothers have blackberries and we use this to text since it uses data vs. text messages just like BBM. It is also available on the iphone if you have friends with one of those things.
You can enter a status also just like BBM and it has a popup message when someone sends you a message. You can also choose a color led light for incoming messages.
I tried Kik and it was ok, but it lacked a few things and now that BB users cannot use kik it wasn't worth it.