They are pretty much a tank tbh. Yiu would have to REALLY hit it hard with something to do damage to them. The 3 I've ran on my shotguns have gone through all kinds of abuse and never had an issue.
I upgraded to a ff4 last year on one of them and the screen broke when I smashed it in a rock crawling in a field. Emailed Burris when I got home, they sent me a shipping label that day and I had a new replacement in 3 weeks. Pretty good service.
Rain however is always an issue on these types of sights and that not limited to Burris. It does come with a rain cover that helps a ton (FF4 has a much much better version of that cover) but I've killed more than a few birds in the rain with it. If the inside of the lens gets wet it will put a big star burst on the dot that can be a challenge.
I usually coat the inside and outside with rainx fog proof solution and that does help some.
I also bought a few rubber covers on Amazon made for the ff3 and I keep them on the sight unless I'm hunting. Keeps out dust and moisture and adds some protection to it as well