Well the decision was made four months ago and I don't regret it 
I hate Robyn - why spoil a perfectly good word? I agree that Robin is unisex!
I think we may have set a trend judging from a couple of recent threads. 
But yes people do assume there's a y which is a tad annoying, and old fashioned. Or assume she's a girly looking boy in girls' clothes 
. Still it's a good conversation starter. And it's not nearly so annoying as the constant mis-spellings of my son's perfectly normal name!