Well, I have used Messages+ and BiteSMS with IntelliscreenX and I have to say, BiteSMS is a little better In terms of features/bugs. Messages+ would have this little bug that if I was in a Messages+ chat and I clicked a banner for another chat, the keyboard and text input box would disappear into the background. Not a major issue, but still a problem when you want to just send a text. Why I prefer Bite over M+ is because of:
1) AUTO RESEND OF FAILED MESSAGES!
I am on Rogers Network and sometimes when I am sending a text at the same time I am receiving one, the text will fail to send, and I'd have to open up the messages app to resend it. Bite has an option to resend messages after 1,2,4,etc minutes of it failing. Total life saver.
2) LOADS WAY FASTER THAN MESSAGES APP
Bite actually loads 2 seconds faster then the default messages app, and trust me it makes a difference when you text a lot.
3) CUSTOMIZATION!!!
You can change pretty much ANYTHING about Bite, where as M+ is pretty much set in stone.