I'd agree with everything you said Whisper. The only thing I would change is that my tubs dont have humdity issues. The water bowls spill enough water when sliding the rack in that the humidity stays good with paper towels and the tubs are FB70s with no holes. However, i still do not have an issue with humidity in my V18 60 slot rack and all but one are on paper towels.
I think the biggest pro for paper towels is the time it takes to clean. I lucked out and found some paper towels from BJs (a bulk store on the east coast) that fit the FB 70s nicely.
I'm sure its not that big of a problem but I also prefer the paper towels due to their almost 100% inability to be injested or pulled into the cloaca.