If the M3 is a bigger and better M2 then I probably would like them. I find the M2 more of a fun earphone and can probably substitute my HJE900 in that category. It does have a slight boost in the bass area and I did a short comparison with the HJE900 since I received a PM about the two and it does seem like the M2 has more weight in the bass which is something I was surprised at. However the M3 probably isn't very practical with the M2 already in my possession and the HJE900 gathering dust as the days pass (I need to sell the HJE900 whenever I get around to it) unless of course someone wants to give me a M3 which is very unlikely :)
The NE-700 does seem interesting and I've never heard a Nuforce earphone so if the NE-700 is competitive with the other top models in the sub $100 earphones then Nuforce probably has made something quite good and the competition in that particular price range continues to get more and more difficult. It's never been a better time to get started in this hobby and spending not as much money to get much better quality than just a few years ago.