Wayward Son's springs are very well made, nicely priced, and recommended highly by many on this board.
I prefer (and use) the IST EZ spring straps Peter_C linked. (although I would buy them from DiveSportsOnline instead of LeisurePro: http://www.divesports.com/mall/innovative_acc_springstrapsjetfins.asp) I find the thinly-covered straps I've tried (not WS's but similar) bit into my Achilles' tendon a bit too much and were not as comfortable as the wider rubber heel cup on the EZ straps, and the pull loop is very hand as well, for both doffing/donning and hanging.
I prefer (and use) the IST EZ spring straps Peter_C linked. (although I would buy them from DiveSportsOnline instead of LeisurePro: http://www.divesports.com/mall/innovative_acc_springstrapsjetfins.asp) I find the thinly-covered straps I've tried (not WS's but similar) bit into my Achilles' tendon a bit too much and were not as comfortable as the wider rubber heel cup on the EZ straps, and the pull loop is very hand as well, for both doffing/donning and hanging.