I've only used the smaller sizes and they work great. Easy to learn/use. Fallen on them plenty of times with no negative outcome. Straps can fray over time. Maintenance is as much as you would expect from nuts/hex's but not as expensive as mechanical cams. Will not work for very small cracks, but this set will fill holes from 1/2 inch to 1 1/2 inch. Also sold as singles, check it out.