whats the reason why they say that Yamaha is the best for HT ?
As far as I know, Yamaha has that reputation because of the satisfaction that product users have had over the years. Not just because of quality but also of price and performance. And of course, the awards they get, too. But I think the reason why they've become the leader in HT is the fact that they were one of the pioneers in DSP technology. Right after Dolby Laboratories came up with Pro-Logic, Yamaha had they're own research and development team. Yamaha, in a true Japanese fashion, developed their own DSP technology. This is now known as Yamaha CinemaDSP. This is not only compatible with Dolby and DTS formats but also enhances it. Resulting in extraordinary reproduction. It can also work on it's own with multi-channel sources. Some have tried to follow suit, like SRS' Circle Surround, Harman Kardon's Logic 7, etc., but Yamaha seemed to be the most successful of all these "in-house formats". So, in my opinion, that is why they've always been a force to reckon with.