Glass ons look cooler, but it sure sucks to have to pay for board repair in the event you snap a fin off. Easier to just pull the broken off nubs out of the fin box and to slide in another fin. I like the option to switch fins personally.
This. I have snapped way to many fins surfing low tide way to far into a sandbar and tried to cut back into the wave and snap.... most time its just the fins and one time I lost a fin housing (cost me $75 total for the housing and the fins).
I wouldn't want to know the repair cost on glassed fins...I have two boards in my quiver that have glassed fins. One is my oldest short board I kept from when I was a grom that my kids use and I have a semi-gun that also has glass fins but I have only used it twice since its not needed much here and I have another gun I travel with..... with FCS housings.