DMM is still going strong, i doubt it will disappear for a long time to come. Do mind though that the same devs that handle nutaku aigis handle dmm aigis since nutaku never got their hands on development rights for the game. So you'd technically go and play more of their game when they are part of the reason the nutaku version shut down. If you do not care about this, then fine, it is all good. If you do, well then i guess you have problems :P