We, at Stock&Buy needed a simple solution for our customers to customize their invoices and documents generated within our systems. Docx templating using Mail Merge functionality is quite known in the industry and our customers are very familiar with it. We started looking at available packages and we were lucky to find Gembox.Document. The library is very simple to use, has powerful and standardized APIs. The bindings to .NET objects is an amazing addition that simplifies the development process. The pricing model is very reasonable and the support is second to none. We recently reported an issue and we got a hotfix within 12 hours which is amazing for a software provider. This library is a true gem and we highly recommend it to anyone in the lookout for affordable, simple, and powerful Mail Merge library.