Oil varnishes take longer to dry. But you are right, it is a real nice look and feel. Some folks say that the wood can vibrate more with oil. Some say hard varnishes stiffen the wood - for better or worse. I have a Collings MT with a gloss front and mat sides and back and I wonder if that has any effect at all. All I do know is that they are able to paint a 'sunburst' halo around the thing and cover up the wood grain.
When you see the complexity of what you think is simple, you will see the simplicity of what you think is complex. - Jamie Andreas