Professional trading and forecasting tools and connecting them with MetaTrader

 

I have read many topics about connecting MT with Matlab via DLL,files or special library. Also many people try to use R to help Expert Advisors with forecasting and data analysis. I know there is possibility to make communication with MetaTrader via sockets, pipes or database. There are many methods to do this but no one is considered as proper or the best. So I have 3 questions for people who know how to trade pro, use advanced math and maybe know how commercial systems work (like in banks) work.

1. Do commerciall companies (I mean not individual home traders but teams of experienced people) still use MetaTrader or have own much better and complex tools?

2. Is it popular in professional approach to connect MetaTrader with external tools like Matlab, R or custom programs to make real-time calculations and forecasting?

3. If it is popular and reasonable, what tools and ways of communication between them and MetaTrader are considered as the best?