Jeff has a point.
Both Chains and Straps are safe, if you understand the proper application of them.
Chains are used to provide a solid, static connection between a load and a puller. Whether that puller is a come~along, or a vehicle, it does not matter.
Because the connection is a solid, unforgiving one, you do not want to induce a shock load. Shock loads break chains, and they break Jeeps.
"Snatch" Straps are used to provide a more dynamic connection between a load and a puller. Because of this, they do not work with a come~along, and do not do static pulls well. Clubs like them because they provide a softer connection between the load and the puller. A strap can allow you more pulling power in low traction conditions because you are using the puller vehicles momentum for the pull, not brute force. Straps also do well as Tree Savers. Their width and softness saves the bark. I have seen a tree cut in two by a winch cable- not a pretty sight.
The draw back of chains is that if used improperly, you can break more hardware than the chain.
The draw back of straps is that they store energy, and if that energy is released uncontrollably, can be be dangerous. An example of this is a strap with hooks. If a hook comes off during a pull, that hook now becomes a homing missile. It will head toward the end which is still attached to something.
In short, know your equipment.
Ron