There is a company over here that makes roll cage kits for weld in cages. Before they will sell you a cage they send you a sample joint that you weld & send to them for inspection. Only if the welded joint passes their test will they let you assemble the cage yourself. One time I priced it up & when you count your own man hours and consumables it was very little more to send the shell to them & let the pros do it! At least then you are sure & you have a piece of paper from the company to certify the cage!
Still is the company. They do majority of high end rally cars and i have seen a few involved in big incidents where both passenger and driver have walked away.
I agree with cages in some sense but I do have an issue with door bars as can make it horrendously difficult to get out unless the doors are fully wide open and even then need a wiggle.