I agree it has a very nice meaning but the sound is not conventionally pretty. All those awkward consonants together...the pz transition is especially difficult to get used to. It also has a very distinctive Old Testament feel which might put some people off.
Hepzibah does have a kind of lumpy charm though.
I think I prefer
Hephzibah with an "ef" sound. Actually I am really warming to
Hephzibah with
Effie as a nickname so thank you for making me think about
Hephzibah!