Getting a comfortable bicycle seat depends on a several things. First the seat, but almost as important as the seat itself is the fit of the bike. If you are not properly fitted on your bike your seat will never be comfortable.
The seat angle is important. The angle of the seat is adjustable in very small increments usually. If the nose of the seat is too high or too low it will make you uncomfortable. With the nose of the seat angled down too much you will also get more weight on your hands.
The seat can be moved forward or backward also. Sliding the seat forward will raise your head a little and change the angle of your back. It will also bring the pedals a little further back in your overall position.
This is one of the most common problems. Too low of a seat height will make your bottom sore when you ride. With a low seat height you do not transfer enough weight onto your pedals so all your weight will be on the seat. If your seat is too high that will make you uncomfortable also.
If your hands are positioned too far forward or to low that can make you uncomfortable.
And Finally the Seat itself is important. At the Bicycle Hangar in Missoula we have several different seats and can help adjust the seat height, angle, and position to help make you more comfortable on your bike. Often we can change stems to move your hand position also.
A comfortable bike is a lot more fun to ride.