The customization is amazing. Every module and menu item that you create for the component can be configured individually and there are dozens of options that you can choose from. Even the checkout process can be modified and fine tuned down to exactly as you'd want it.
This is by far one of the best components I've ever used and I'm very happy that I've switched from VirtueMart over to HikaShop. I'll never look back.
To say that this component is buggy is an understatement. I ran into dozens of fields that simply wouldn't work. For example, I couldn't edit any of my User's Details and I couldn't get pricing attributes to ever save. Most times I had just gave up and had to edited the databases manually. Lots of times, the pages wouldn't load properly when I was configuring it, spitting out tons of errors.
Their documentation is actually rather good, but documentation only goes so far. The rest of the time, you need some good support and there simply is no support for this component. All of my threads on their forum went completely unanswered. From what I saw, most threads on their support forum go completely unanswered. They like to point out that their forum for community support, but that community needs to be lead by the devs which I didn't see at all.
You may like what this component offers; you might think that this or that feature is a killer that you can only get from this component, but trust me, it's not worth it. Don't even waste your time installing it. Try out some of the other great alternatives.