Neither do I.
The difference between Bobby and JR was the way they operated. Bobby certainly had the moralistic point of view most of the time and JR the amoral way. JR wasn't above blackmail or coercing someone to do what he wanted like poor Edgar Randolph. However Bobby wasn't above getting his hands dirty either witness the sting operation he and Ray pulled on Walt Driscoll which resulted in the car accident which paralysed Mickey Trotter.
As to which was the better Oilman I would say JR even though his methods were not always ethical.
Bobby I guess was a good Oilman but only really embraced Ewing Oil more when Jock died and that whole battle for Ewing Oil as a result of Jock's will.
JR should've ran the company. If it hadn't been for Miss Ellie pressuring Jock to let Bobby run the company when JR was incapacitated as a result of the shooting Bobby would never have got the fever for big business. Especially when JR wanted the company back and Jock said he couldn't do that because of Miss Ellie not wanting Bobby and Pam to leave Dallas.