Hey, it's awesome to see you back! The site has gone through some changes over the past little while, any thoughts on them?
You can see if the product has already been added to the site by searching the product name > click "Search: product name" > filter by "products". If you see it there, clicking it will take you to the product page which gives you a list of questions the product appears in. Going to any of those links will let you add your pros/cons.
If you don't see the product, you can search questions you think it would fit (or ask your own) and add your review.