Denim: Fantastic work. The guy at Sydney's recommends here for high-end jean repair. My boyfriend trusts no one else to fix blowouts in his designer jeans. Very intricate and detailed work - noticeable fixes, but very very well concealed. Price is reasonable considering how much work goes into those repairs.
Everything else: Meh. I took in a $20 dress to get it taken in in the sholders. Cost me $30 to have it altered, and the shoulders are still a little too big.