Welcome back, milz! Haven't seen you in awhile.
Not sure why you've had such bad luck with the 9900, but I don't know if I'd "downgrade" to the 9790. And it would definitely be a downgrade. You would NOT be happy with the 97xx series after having the 9900. If you aren't dead set on BlackBerry, why not try something else? What other options do you have from your provider?