Recommendation: Use them and replace them with nicer shifters. Don't try to shift under load either. Not bad because they are so cheap, but they do the job for light riding. Just don't expect too much.
Pros: Great entry level rapid fire shifting
Smooth action on the levers
Can take a beating and keep working fine
Recommendation: If you are looking to move into the rapid fire shifting scene, the Alivio setup is the way to go. You can easily bang down through the gears and with the push of a thumb, work your way back up to the taller gears when the hills arrive. Very smooth and with preventative maintenance, will last a LONG time.
Recommendation: These shifters provide great quality shifting, if you like the rapid fire design. Even if you don't like the rapidfire at first, I can almost guarantee you'll be used to it after a couple of rides.