Malimo

Langify has all the features we need and works well. Also they have truly awesome support. If all support was that good the world would be a better place.

I find the app very useful because of the 'connect similar products' feature which lets you show swatches on the product page that link to other similar products in your shop. Also the way variant buttons and swatches are displayed is very customizable which is great. Service is also very responsive and friendly via instant chat. Only downside is the price, I think it is a bit expensive and they should consider lowering the price, otherwise I'm sure sooner than later a competitor App with the same features and better prices might appear.