It depends do you need full coverage of sides and back or do you just want the sides protected and back exposed. I have owned both and I prefer the EX because of looks I like having my back exposed lol. The one issue I noticed with the Matte is that the back starts to sag after a month or so. Also if you search for SGP Neo Ex there is a huge thread about both.
FYI both(Matte and EX)of the colored plastic frames fit tight and you need to be careful with them and slip them over the front not the back. I found this to be the easiest way to put them on especially with EX as it can be tricky with the rubber part moving around as well.