Would have to agree, your average 109 stick is going to be a better fight and likely a better pilot than your average P-51 stick.
I've met a few good P-51 pilots and even had the pleasure of beating some. KrapGame was pretty good when he was still around, a lot of the 91'st were good in it, and so are some of the BK's (I think its the BK's anyway).
I'm capable in it, if not what you would call great, and it used to be my main ride before I went luft. I know it well enough to say that a lot of the whining is caused by people asking for the P-51 to tie their own hangmans nuse.
But still, one all's said and done, the average 109 is still going to be better than the average P-51.