I was nervous, too, before buying 4 Midwest implements sight unseen. Had heard of the quality for the money. I have a 4310 with I match and both the blade and rake fit perfectly - haven't used the aerator or the rotary cutter, but they appear to be a good match, as well.
I'll be posting in more detail later about my experience with the implements. After a weekend using both the blade and the rake, I'm thrilled with my purchase.
My vote: don't hesitate - great value for the dollar.
Bill