best? that's like asking what color is best.
both have uses.
as weights hauled go up, chains become safer. i like a 'strap' to be rated abt least 2 x of the total load being strapped. IE.. if I am hauling a 10K tractor.. i want 20K straps.. even if I am using 4-5-6-7-8-9 straps. i want each one to be 2x the rating of the entire load. Obviously as you get heaviner loads.. it gets non economical to have strapping rated for that.. even though you can get 3" and 4" straps.. .. once you get over 2"/20k straps.. it becomes cheaper to go chain and binder.
for most applications.. i like straps.. they mar the paint en metal less. if i'm going out of state.. i might have a chain for and aft, then fill in the ballance with straps on all corners, straps on each implement including attached implements like loaders and hoes and mowers, plus a cross strap across the trans.
I err on the side of more is better.. a minimum of 1+1 strap per 10' of load, +1 per implement, AND all 4 corners tied independently.