Yes, they are very good cars, provided you're after a fun, cheap sportscar.
The Ford Mustang has a lot going for it. It's cheap (starts around $21,000 for the V-6 model with 210 horsepower and $26,000 for the V-8 model with 315 horsepower). It has decent reliability, excellent handling, lots of power for the V-8 model, and isn't a huge car. They get good gas mileage, look awesome, and are cheap to repair, easy to work on, and have a load of available aftermarket and dealer-optional parts to make it look and go even better. Interior design is top notch, and you can customize that as well straight from the factory.
The only real downsides to a Mustang are a small rear seat and your insurance cost will be a little higher than a standard midsize car because the Mustang is classified as a sportscar. However, if you're considering buying a midsize coupe like the Mustang, then rear seat room probably isn't very high on your list of priorities.
I'm not sure where you heard that Ford vehicles all suck. There are a few low spots (American Focus, Crown Victoria, Ranger), but look at some other areas. In reliability, Ford and Mercury are now ranked first and second, ahead of Honda, Toyota, Buick, and Subaru, the previous leaders. Plus, look at some of Ford's upcoming vehicles, like the F-150 SVT Raptor, which is basically a street-legal Baja Pre-Runner. Or the Taurus SHO, a 365 horsepower All-Wheel Drive monster of a car. Or the Focus RS, possibly the world's fastest, sportiest compact car, available in Europe now and possibly by 2012 in the United States.
If the Mustang just doesn't quite fit, your only other choice for a midsize, Rear-Wheel Drive coupe is the Hyundai Genesis Coupe, which comes with either a 200 horsepower turbocharged I-4 or a 306 horsepower V-6. The Chevrolet Camaro and Dodge Challenger are both much larger than the Mustang and Genesis, cost more, and aren't nearly as much fun to drive (though they both look awesome).
If you don't mind switching to a Front-Wheel Drive platform, there are a few more choices out there in the form of the Honda Accord Coupe and Nissan Altima Coupe, which both offer an I-4 or V-6 engine, with the I-4s making around 170 horsepower and the V-6s making between 270 and 280 horsepower, but Front-Wheel Drive isn't nearly as much fun or sporty as a Rear-Wheel Drive.
I still recommend the Mustang.
I hope this has answered your question. If you have any more, please feel free to ask.