Its got a very smooth motion to it, and is very easy on your back and joints. Its very easy to adjust your feet to as narrow or wide a width as you would like. Personally, I always squat wide. There was a study that came out showing the quads get the same workout no matter what the foot position was, but the hamstrings and glutes are worked much harder when you have a wide stance. They found this by hooking up electrodes and measuring how hard the muscles were working in numerous test subjects.
If your gym has one of these, I highly recommend it as an alternative to squats if you have any issues that prevent you from going as heavy as you would like. Hammer Strength is a very respected name and their equipment is top of the line. NFL teams swear by Hammer Strength equipment, and with football players undergoing the most rigorous workouts in sports, its a pretty good bet whatever they decide to use is a really good piece of equipment, considering they have the money to buy whatever piece of equipment they choose...
Squats are great, if you can do them...if not, you can always use the V-squat and get excellent results with that as well...
Here is a picture of the machine:
Rob also requested a link as to where you might be able to get one, so here that is also:
https://www.usedgymequipment.com/fitness ... V-%20Squat