Complex sentence: Users have the option of personalizing the product ranking based on preferences (weightings for different criteria for a given product/service) and can also view product specifications, read reviews of the products and compare selected products.
Split into simpler sentences: Users have the option of personalizing the product ranking based on the their preferences (weightings for different criteria for a given product/service). They can view detailed products specifications, read the reviews of the products and compare selected products.