I got the Yamaha NS-FP9500 free from Bestbuy with a tv I bought. Are they any good? I am currently using the Onkyo SKS-HT510 and while the sub is decent I don't really care for the speakers all that much. Would the Yamahas be much of an upgrade? They are more expensive but that doesn't always mean much. I am just trying to decide whether to keep them or sell them on eBay.