Just wanted to share my experience with my shoes.  I remember owning a pair of Hi-Tec squash shoes, as these were the most suitable I could find from my local high street sports shop at the time.  This was way back before the days of internet shopping.  These were fine when the courts were clean, but more often than not, they would be dusty and therefore I wouldn't get the squeaky friction sound at all. 

I played/struggled on with these for years as they were hard wearing and I didn't know any different.  However, admiring other players shoes, I noticed that their Yonex shoes seemed to get a better grip, at least judging by that squeaky sound, so one day I decided to take the plunge and splash out on the top of the range Yonex ones at the time ( Yonex SHB99 LTD ), this time via online shopping.  Eight years on, I'm still wearing these!  Admittedly I did take a couple of years out from badminton but the shoes are still going strong and I still get a good grip with them. 

On my squeaky test, I think I get more squeaky sounds than a friends Asics, though this is far from a scientific test of course as movement pattern will play a big part.  I've tried a pair of Victor SH9000 and I love the design but I found them a bit too narrow for my feet.  I also felt I could not get as good a grip with them as I can with my trusty Yonex pair but maybe the SH9000 needed wearing in a bit.

The soles are starting to go now though on my SHB99 LTD so I'm going to be hunting for a new pair soon.  I will probably wait until the 2014 releases before I take the plunge, but it will be a sad day when I have to retire these!