Both are OK but It really depends on the thoroughness of the person DOING the cleaning. Just like vacumming your home- you can be meticulous. Cons: With the VPI- you contaminate the cleaned side when you flip it over onto the dirted mat to clean the other side. With the Nitty Gritty- Because you insert the dirty side down, you have to make sure the cleaning solution is getting evenly distibuted and the LP is getting evenly scrubbed & vaccuumed. Good Luck
