If you only want to choose between these two, I can only recommend the 16.5 because that's what I use.
Are you sure you want to limit yourself to these two choices only? How much time and effort are you willing to put into lp cleaning? What is your budget?
For the ultimate in lp cleaning on a budget, steam is without question the choice, IMO. Again, that's what I use in the 1st step. Some people like the Spin Clean, but I don't like the dirty fluid getting on my hopefully clean lps. I use a pre-cleaner of AT enzimatic, then steam, then a 2nd step (AI) on my Record Dr., then a rinse on my 16.5. I never worry again. That's important.