My son is making fantastic progress on the sax, is now up to grade 5 at the age of 11, and plays soprano and alto. The alto, however, is a pretty basic beginner's sax and comparison with a borrowed sax shows that it's definitely letting him down. Time to move on. A Yamaha YAS-275 has been recommended, but I don't really want to have to upgrade again in a couple of years' time, so I'm wondering about a used Yamaha YAS-475 or indeed a used YAS-62 (at a budget of under £1,000). Does anyone have any thoughts, recommendation or advice?