The best thing about this system has to be its ease of use, it's very simple when you are new but as your business grows so does whizzhops capabilities! Nothing at all really what I dislike most would have been if there was something that didn't work well however we never had any issues or problems like other systems do sometimes (think Paypal). We used their payment gateway called payflow pro because they were one step ahead in terms payments security etc., also using thier integration services saved us time by having everything done through them instead doing our own integrations into another platform such as Stripe/PayPal ect.