This is the thread for Yamaha Tyros 4 vs. Motif XF and I'm sure it will be interesting considering that both have their loyalists.
The Tyros 4 is a great arranger but has limited programming abilities compared to the Motif.
So if you are a studio guy and like to create from scratch then you will definitely like the Motif. The Tyros won't have sampling, no pattern sequencer, no multichannel Firewire audio interface...enough reasons to put-off anybody who is keen to create his own unique sounds.
On the other hand if you are a performance guy, like simulating a live band, and want the instruments to sound as real as possible, then you will like the Tyros. You have more control over the performance related nuances on the Tyros compared to other keyboards.
Here's a video performance that incorporates the Tyros and the Motif
Tyros and Motif are the flagship products from the Yamaha brand. If you have been playing keyboards for some time and thinking of an upgrade, you need to understand that the Tyros is an arranger workstation, whereas the Motif is a Synth Workstation.
The Tyros is a great arranger but has limited programming abilities compared to the Motif. Motif gives you more and better effects, as well as other music creation/editing tools.
On the other hand, if you are live performer / singer, you'll mostly prefer an advanced arranger because of their chord recognition feature, top class accompaniments that can be readily used, and the vocal processor which is really useful if you're a singer or have a singer in your band.