Does the MP100 play as stiff as the TI-10? They both say extra stiff in the yonex catalog.

Not really. I went to play badminton last Saturday and I was switching from a Ti-10 to an MP100 from time to time. After using them both, the MP100 is less stiff than the Ti-10. When I hit with the MP100, it seems slow. But when I hit with the Ti-10, the speed was just so quick.

I have one, and I think it's soft. In fact I don't use it very often.

Its a relatively soft/flexible racket, depending on how you know it as. I was at the badminton shop the other day and the man there showed me the MP100. its very expensive and flexible. I prefer my rackets stiff. Personal preferances i guess..