I play three banjos with some regularity. I have a fyberskin on my Fairbanks Cole that I play with nylon strings. It is great, and a lot prettier than the frosted white one that I replaced with it. I usually play a Vega Style F tenor, in Irish tuning and have an ugly plastic head on it, but it works and I like the sound. I use a skin head on my Orpheum #2 tenor but never have liked the sound until I put standard strings on it and bang out chords.

Different banjos and styles sound better with different materials. As for replacing, I wouldn't bother if you like the sound. You might want to get an extra just to be prepared. I came home a few years ago to find that a head had busted while I was away. It looked impressive and I was sort of sad I missed the excitement. :S