In the last few years we have worked with a lot of external developers to improve our magento store, and Biztech is the best company which we have worked with.
We chose Biztech to work on our last project, an online t-shirt designer in html5. They have developed an extension that had what we needed. But we also got a long and complex list of custom features incorporated in the t-shirt designer tool, with totally new skin and very complex calculations. Biztech has a special team with magento certified developers, so they have the required know-how, and can develop any feature or fix any bug/issue very fast.
What we also liked about Biztech is that their support team is very professional and friendly, with huge patience. One surprising thing for me was that one time when we had to contact the developer directly, we found that he was very friendly, and understood our requirements fast. This is something not commonly found in developers of other companies and and we normally have to put in extra efforts to get out point across to developers.
Biztech accomplished everything that was promised to us. We are very happy with them, and actually are in the process of starting bigger projects with them.
We can recommend Biztech 100%. KEEP IT UP