I've had good luck with both National and Timkem products. Just make sure to look at the parts before you plunk down your greenbacks. These companies are global companies and the parts inside could have many locations of origin. The front wheel bearings on our LBCs are a very common size which also means lots of suppliers. This makes lower quality suppliers want to sell these popular sizes. So again, open the box in front of the seller and see where they were made and what the visual perspective of quality indicates. Compare them to your old ones and look closely. Timken is good, usually boxing their own product from one of their manufacturing locations anywhere around the globe. National would likely box a Bowers bearing from one of their locations. But this doesn't mean that you won't find something else in the box for that size bearing.
Timken also has many facilities in the US providing jobs to its citizens. One is not more than 2 miles from my house making the Torrington product line. So, I'll vote for them. They employ my neighbors and fellow taxpayers albeit, not as many as need jobs.
HTH,
Mike Miller