Although
Heather suffers from the same sort of gustiness as
Hester, it doesn't hiss bitterly like
Hester seems to do, to me. The -ther pleases me more than the -ster. YMMV.
Harper is not more appealing to me than
Hester.
Harper sounds like it's trying to be statusy, while
Hester just sounds homely. But I guess
Hester sounds better than
Harper, because
Harper reminds me of harpies.