I actually have had pretty good luck with ECS in the past, at least for stock-clock machines. Not sure how they are now, but I'd try them again if building for someone else (I mainly buy Asus or Asrock now for myself). If I was building an mSTX machine I'd be inclined to get one just because they're interchangeable. But that's not the most important part about this development anyway. The thing is that now OTHER motherboard makers may very well release mSTX boards with the same standard IO shield setup, and more case manufacturers could join in too. Ultimately if this catches on it will benefit everyone even if you don't use ECS.
Link? The article says "Thus far, all of the mini-STX motherboards we have seen can be used in just a single case each" which kind of implies there is either no standard or they don't feel a need to adhere strictly to a single layout. It does seem rather limiting and I'd rather see conventional IO panels take over as a de facto standard if the actual "standard" is that restrictive.There is only one arrangement for the rear IOs, this is what STX spec defines and so all STX boards/chassis are compatible. Once ECS changed the rear IO, it is another proprietary design which cannot be called STX any more.