Filterific: Collection Filter

My store is still in development, but I have been very impressed with both the function of the app as well as the very attentive service I have received from the developer. I needed a side-wide size filter based on variants, and this is working very well. Emails were returned promptly, and a bug on their end was found and fixed quickly. If you need filter functionality that Shopify alone cannot provide, for the price and this level of service, I think it's well worth it.