853 is as tough as the builder wants it to be, it's available in more diameters and gauges than any other Reynolds tubing. A superlight TT frame won't be as tough as a burly dirt jump frame. Size for size, 853 is stronger than 4130, but that extra strength is usually exploited in thinner walls rather than using the loads of material to build an ultra-tough frame.
853 is as tough as the builder wants it to be, it's available in more diameters and gauges than any other Reynolds tubing. A superlight TT frame won't be as tough as a burly dirt jump frame. Size for size, 853 is stronger than 4130, but that extra strength is usually exploited in thinner walls rather than using the loads of material to build an ultra-tough frame.