Upper body protection has been a regular feature of the sport for the past 20 years.
The areas vulnerable to injury are the shoulders and the chest, which often take much of the impact in tackles, so it's important these areas are well protected.
Modern upper body protection is made from very strong and lightweight material.
Again comfort is the most important factor when considering chest protection.
Make sure it fits you well, otherwise it will be extremely uncomfortable on the field, as well as increasing your chance of picking up an injury.
But remember, wearing body protection doesn't mean you are invincible and can do things others rugby players can't - you'll do yourself more damage if you think like that.