I love playing matrix's for many reasons. First off it reduces variance w/o increasing downsizing. You don't find yourself losing as many beats.
You also are able to get 4x the read on your opponent, which allows you to quickly find out how the other 8 players play poker.
Most Importantly, I feel like it allows you to play more aggressive than you normally would if you were 4 tabling sng's. If you play too aggressive 4 tabling sng's and you get knocked out of one then you've lost a buy in.
With matrix you can lose out of a table and still easily make you money back, and usually still make a substantial profit. (I finished 9th on one table, 3rd one one and two 1st places. and took 1st overall.)