On my Droid RAZR, every time I send a text, I get an arrow which I assume means sending. Sometimes, I get a nice little message that says the text was sent, and the time. Other times I get a red X and a "message not sent" error. But about 80% -90% of the time, I get the annoying arrow, and I have no idea if my message went through or not. Sometimes, days later, I still have an arrow. If I send a text and it's actually important, I have to ask the person if they got it, then wonder if they got that text too, although usually sending a second text causes the first one to resolve and give me a time it was sent.
My girlfriend has the same issue on her Droid RAZR MAXX, although not nearly as frequently as I do.