Not really. It seems to be more what the dentist makes or prefers but until this last bottom splint, I hated bottom ones. They were too big and bulky for my small jaw. This current one just basically covers my teeth without the bulk. My tongue and mouth like it better and it works great.
But it may be the bulkiness of the splint or lack of bulkiness that I like so much. It's seems to be doing what it's suppose to and my symptoms and pain have greatly reduced (i've made other changes too though).
So, whatever you feel the most comfortable with that works is how I would determine what kind you wear. :)
take care and god bless...
Carol