Well, I would get the 55txi if you can afford it. It has I-link, which I think is an amazing feature, but only if you plan on gettin a DVDAudio/SACD player with firewire Such as the Pioneer 47Ai or the new flagship 59Ai.

It also has, I believe more power and features, but I am not sure. But I would really love to have the I-link feature because I love Hi-Res music and this is the way to go for that.