They also have better iron sights than typical MACs have had throughout the years, but you probably want to use a RDS anyway. The trigger pull (from what I've heard) is still not like a well tuned 1911, but you can make controlled trigger manipulation. MPA has a hammer with a disconnector built into it. Handy feature if you like to convert money into noise as fast and ineffectively as you can. The booger pickers love this because you can "bump fire" a whole magazine easily because of that.
When you lull the trigger, it slaps your finger back off the trigger as it re sets. In short, there is nothing that breaks the chain of hammer pushed back by bolt/trigger pushed back by hammer on a lot of the MACs out there. I understand that Masterpiece Arms (one current maker) makes a good product on modern equipment and that they have solved the problem of the finger slapping triggers the semi auto macs are known for. There are guns built to take Sten mags, some that take a proprietary magazine (with zytel and steel options for that magazine) and IIRC the earliest ones took a Walther magazine. Again, a whole lot of unequal choices ranging from top quality to bottom of the barrel. I can see how some of the examples I've seen could be really good with a folding stock, and I can see why so many people see them as range toys because they have handled crap examples. There are and have been a bunch of companies that made them, and they are not all equal.