I just bought my first mustang a few months ago but that was after being around them for years. It took me so long to buy one because I knew what I wut couldn't find it.
I think that the stang is very reliable -- except in the snow unless you change to snow tires but even then you can only be on pretty clear roads but what do you expect from such a powerhouse. I have a buddy that has a '66 stang an the only reason it is not on the road at the moment is he hydroplaned into a guard rail..
If you are looking for a good sound that is not to loud the flowmasters are great. i wouldn't even bother putting the money into a 6.
Why buy??? well they are fun to drive, reguardless if you mod it or not. But they are a lot funner to drive once you start modding it. They are also very distict in their looks. Most of the other muscle cars have similar charactoristics (i think I mispelled that).
Over all.. If you want a fun car to drive a mustang is great in all aspects...