MSS is great... and it sucks
First, I think middle stack strategy is a valid strategy. It seems to work well, however it looks to me like more and more people on the site I play on are using it. There are times when I see that 4 or 5 out of 8 or 9 players are buying in for exactly 40 bb and look like they are using it. At what point do you say, "Ok, do I need to change up to combat this strategy or just stay out of the way of the suspected mss players and target the rest of the table?" For the record I am fairly new to using it, but so far it has been quite successful.