That's what I'm doing. While I did previously use A-Map, and still do when I need to use a tool for mapping, MEH is a lot more capable and a lot less bug-prone, not too mention that it's in active development.
...Having said that, as Prixy said, it's not done and we don't know when it will be. For me, it gives me time to organize my ideas and work. But, at the same time, A-Map 1.92 is still a ready and able map editor that is capable and far from broken. I don't see any reason not to start on that and then make the switch when MEH is ready.