Maybe it will sound like I am exaggerating a bit, but if you are looking for a broker for a long-term commitment, you should consider FxPro. Why?
Because of their track record of being a reliable partner, their commitment to being in pace with the latest trends, the constant improvement of their infrastructure… and possibly because of the huge pool of traders on this platform. It somehow ensures the longevity of the broker and at the same time its solvency.
This is how I understand what factors one should consider for a long-term commitment. I am not sure what your conditions are in this regard.

This is a great broker to start trading through them. They have been running since 2006 and I am sure they will continue to work for a long time.