I know this is an ancient thread, but that's precisely why I wanted to respond. All these years later the apps have changed.
I used Go and stuck with it for well over a year for some incredibly stupid reason. The feature I was most interested in was individual contact notification customization. Go did that, but very badly. To begin with, for no apparent reason whatsoever it would delete my customized settings.
I thought to myself, "Self, try the backup/restore option." WRONG! Once I got the settings all correct I would back it up and when it would delete the settings, I would restore it. Well I don't know what their definition of restore is, but it clearly isn't mine. It didn't restore the deleted settings.
I realized it was backing it up once per week. Maybe when it deleted the settings it backed up just after. So I shut off the auto back up, reset all my settings and backed it up right then and there. Next time it deleted my settings and I restored them, it still didn't restore the settings. Fine.
I emailed them and got a form letter that didn't even address my problem. I replied the way it said to and never heard from them. I did this about five times without any response whatsoever.
Finally, I woke up and just deleted the stupid thing. It was more trouble than what it was worth.
Today I began looking for a superior replacement. I finally decided to go with Chomp and I have to admit that I liked it better right away. The settings were easy, there is also a backup and restore and there is another benefit that you don't get with Go. You can still schedule messages to send later, like for a birthday or if you're up in the middle of the night and you're afraid you'll forget to ask Jane to do something for you, you can schedule the text.
Since you specifically were asking about the difference, I thought I'd chime in. So far so good, but the deleted settings happens within a few days. We'll see how it goes. If I don't post back, then you'll know I didn't have the same problem.
Cheers to future readers and hope this helped.