Well, all welds should be done by certified or at least formally certified professionals. They will know what they are looking at better than anyone else, even a "pretty weld" can fail if improperly done. Truthfully 75% of what a weld looks like comes down to weld prep and position. Things that really matter strength wise are penetration, heat affected zone, weld purity, shielding gas used, and technique appropriate to material. Unfortunately most welding done by manufacturers isn't done by certified pro's, it's generally done by Joe Bob Cletus (no offense to anyone named Joe, Bob, or Cletus) who took an online course for 35 bucks, or worse yet made in chiwan, top it off with substandard quality control and bing bang boom, random suspension part breaks leading to insane accident. Of course, sometimes its just a bad mechanic with poor attention to detail who forgets to double check his work too.