Bel Canto S300 vs Bel Canto Ref 500 S

I have not had a chance to listen to either one of these amps as I live in the sticks! Need a amp for my Maggies need a lot of current . Both amps are rated pretty high power wise but of course the Ref 500 S a little higher. The S300 is being sold for $670 and the Ref 500 for $999.Which is the better buy and why? Any thoughts on the 2 amps would be GREATLY appreciated! Thanks for your help! 
Definitely pay the extra for the REF500S. It's quite a step up from the S300. It is only 50W per channel more powerful than the S300 at 200W per channel into 8 ohms, but it uses a newer and better sounding ICEpower module, it has their impedance optimized input stage and their custom AC/DC input filter and energy storage stage. Between those three changes, it is a considerable step up. The S300 has been discontinued for a long time already and the REF500S is still a current model.
Thanks for the response! Im leaning that way!