VPI HW 16,5 vs. Okki Nokki

The VPI is a great machine. Proven and works with great support. I just replaced a spin clean and there is no doubt the Vpi works much better. Get one and don't look back.

Personally, I'm a Nitty-Gritty guy...real dirty records with smatterings of peanut butter and jelly, I steam clean

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.

I agree, VPI makes some great equipment. However, its current machines are old technology. Ultra sonic is the newer technology and does a much better job of cleaning. So while currently ultra is more expensive, it is the future. No special fluids needed. Rumor has it that Harry is working on his own version of ultra. Those efforts will be a challenge as the patents for the technology in place a very strong. So, if you want the best, beyond VPI and Keith Monks, go ultra. Any don't forget the steam.

Both are great WHEN you use earplugs...