I would strongly recommend that you go for a professional synth, something like the Roland Juno-D if you could stretch to £319
http://www.dv247.com/invt/24460/ the sound quality of this synth is excellent.
You will however also need some sequencing software whereas the yamaha has a built in sequencer for recording and editing your compositions.
It really depends on where you are going with it but the Juno-D is something you might start to build a recording studio on and the Yamaha might be something you would want to replace after a while.
Having owned many synths and keyboards over the years I have only just got my studio how I always wanted it.
If I were you I would try and demo the keyboards before deciding, sound quality is often subjective to the listener.
And as boomboom says, you might want to go down the route of a midi controller ( just a keyboard that makes no noise ) and software synths running on your PC.
http://www.dv247.com/invt/24460/ the sound quality of this synth is excellent.
You will however also need some sequencing software whereas the yamaha has a built in sequencer for recording and editing your compositions.
It really depends on where you are going with it but the Juno-D is something you might start to build a recording studio on and the Yamaha might be something you would want to replace after a while.
Having owned many synths and keyboards over the years I have only just got my studio how I always wanted it.
If I were you I would try and demo the keyboards before deciding, sound quality is often subjective to the listener.
And as boomboom says, you might want to go down the route of a midi controller ( just a keyboard that makes no noise ) and software synths running on your PC.