I like the Holly spelling better. I don't think it's bad....all of the people that I've known named Holly made for some bad associations except for one, my cousin Holly. If it weren't for her I wouldn't like the name at all.
I have a friend that i work with. Her name is Holland but we all call her Holly. We always tease her at Christmas time because her name is Holly Bright. I think she is great! But i would have to agree to Holly over Hollie!