I agree every defense has advantages and disadvantages.
I run M2M or press on all of my teams, and from my perspective this is how it is when comparing the two:
M2M positives: You can try to match your better defenders to their better scorers, and you can use the doubleteam to your advantage. Seems more consistent, probably due to less chance of over fouling good teams.
M2M negatives: Bad defenders can be exploited by good coaches (as the guide says), you don't seem to get quite as many turnovers, and (to me it seems like) you don't have as much chance of upsetting teams who are slight favorites.
Press positives: More turnovers, more chance of close upsets, no chance of weaker defenders being exploited. With good defenders you can take the ball away well, especially from their low BH guys.
Press negatives: You can't put your best defenders on their best players and there is no doubleteam to shut them down either, so you can get lit up by good scorers. Sometimes you can get into foul trouble, and if it's one of your better players you hope your backup is good enough, so you need to be deep to compete well.