Felt also has its disadvantages on muddy banks!
I have rubber soles on my wading boots because my fishing/wading tends to be in the mud, sand or gravel of the lower reaches of rivers, or in saltwater. If I was fishing the upper reaches of rivers more and wading on rocks, then I would tend to felt soles.
I would suggest assessing how much you wade and the speed of the water and the type of river bottom where you do. Also consider how much you walk on muddy ground to get to your fishing grounds and balance that against how much wading you do. Are you truly wading to cross channels, or are you mostly just standing in shin deep water? Lots of considerations to balance...
There are times I wish I had a pair of felts, but for 95% of my fishing, the rubber soles work just fine.
Another option is to buy a pair of Korkers with interchangeable soles, but it's too much of a pain to change in the field.