Not really sure myself.
A womans vagina is very versitile when it comes to adjusting to size-- big or small. Yes- women are different sizes on the inside- but I don't think it differs as much as for men. Its more about tightness-- and there are excercises that can increase a womans tightness. (i.e. kegel)
I also don't buy the whole-- 'big penis stretched me out' thing. Vaginas are elastic and tend to 'spring' back-- so to say. Yes-- having a baby can really stretch it out-- or extreme insertions can probably stretch it out-- but I'm not convinced that large penises can stretch it out permanently.
I've had different sizes of dicks throughout my life (the same one for the last 11 1/2 years)-- and can find pleasure with each one. Its not just about the dick whether sex is good either- its more to do with the man, and who he is and what techniques hes willing to employ.
Yes theres a different feel for each man-- even if their penises are the same size- just as mens hands feel different, their bodies feel different and even such things as hair and skin feel different. How they touch you feels different-- not necessarily better or worse-- just different.
My husband is on the small side of average I would guess-- have never measured him-- and he feels fine to me. Yes- I have had dicks that really filled me up- but it didn't 'ruin' me for smaller dicks. I love my husband- and that plays more importance for me then his size.
Anyways- a very large dick oftentimes can't fit all the way in anyways- or if it does- it can cause more pain then pleasure.
Its really whatever works between two people. What one woman might see as a small dick- another woman might find just right.
Decide. Commit. Succeed.