I actually posted a response back to Chony and I will re list it here in case it has been missed:

Great review Chony,
I do agree where you state that the T4 is an UPDATE not an UPGRADE.
It does depend on the users requirements though. If you are huge into sampling than the flash memory is a MUST and this would make this a huge world of difference over the previous Tyros models.
Yamaha decided to create 3 new drum kits in their Arranger workstations. YES this is great and long time needed but they should have done this to more drum kit categories…
The spec list shows over 30 drum kits now on the Tyros. To be honest they could do without half of them because just one of these new kits makes some of the older ones completely obsolete in my opinion.

I still can’t believe Yamaha has not created a new acoustic guitar sample since the SA concert guitar on the Tyros 2. Yes it’s a fantastic guitar voice (my favourite across every keyboard on the market) but you need variations!!!

The ‘new’ piano on the Tyros 4 does seem to be ‘hyped up’… the standard Grand Piano on the Motif XS was still better in my opinion and the key off sampling on the Motif line is much more visible to the ears. This Motif XS introduction video should explain it a bit better: http://www.youtube.com/watch?v=jGS_O0LRnCA

On the Arranger workstation line (Tyros), Yamaha do seem to use a lot of marketing fluff… i think the whole super articulation / mega voice stuff is all hype.
A Megavoice is just a voice or patch that has multiple velocity switching samples and different samples throughout the octave range.

Any of the voices on the Motif XS/XF can be tinkered to become a ‘megavoice’. None of the Motif voices are actually named Super Articulation voices because they mostly all have the same characteristics and can be controlled in a very similar way.

The Motif XF has the new “Section Strings” voices as well as the big Orchestral Tremolo voice. All these samples (I think) are the ones that make up the new REAL string voices on the Tyros. It’s sort of been kept quiet and un noticed on the Motif XF but the Tyros gets all the hype and attention!

Still I don’t understand why certain people claim that Yamaha are ‘milking’ the market though… If you don’t like it DON’T BUY IT!

Nick