Having an outdoor asphalt court at home, and having been through soooo many outdoor balls, the best I have ever used was the Buffalo ribbed outdoor ball. Ribbed to it felt more like a leather ball. Pimples took ages to wear down. It retained a soft leather like feel right to the end. And it lasted forever. Eventually it egged, but it got a lot of use before then. I bought the last one 3 years ago for only $20 at SportsPower and seemed to remember them being at Rebel too - it may have been a $30 ball in sale but it was a basic cheap outdoor ball. However in the last year I haven't been able to find one anywhere. If anyone knows where they are in Melbourne let me know.
Apart from that I have always bought the Nike ball for $20. It never eggs. But the problem with them is that the pimples wear down fairly fast and then they become quite slippery to hold, catch, dribble and shoot.
Any of the sub $20 balls I have tried have never been worth the trouble.