Bill,
I do disagree with your opinion on the this statement regarding the T4;
"although the brass sounds now fall short of the PA3x (Not by a great margin though) with the synth sounds being its weakest point, so if your into more modern, disco, progressive, New Age then the T4 may not be for you."
I happen to think the Brass sounds are awesome and it's one of the reasons I use it with my Wedding band and to play Big Band music during cocktail hours.
Also, the Tyros 4 Synth sounds are Sound Samples coming directly from the Yamaha Motif XF and those sounds are some of the best of the best. I use quite a few of those sounds even when I perform with my Motif XF. The PCM Synth sound is use on Ke$sha's Tik Tok and I use several Synth PAD sounds on Prince's Purple Rain.
I consider myself pretty objective and not a fanboy of any particular brand as I own or have owned Ketron, Korg, Roland, Yamaha keyboards. I use the best equipment for the job.
I agree wholeheartedly, Al, and like you, the brass and synth sounds are more than satisfactory.
I can't say I am not a fanboy

, but, the reason I am one is because I simply love the sound and layout of the Yamaha Tyros4 more than any other arranger I've tried.
All personal opinion, of course.
Ian