I would avoid Japanese; Asahi for instance.

True in the 70's, not now. Maybe avoid Chinese low-end manufacturers??

SKF used a through hardening steel whereas RHP used a case hardening
process.

Certainly not in small sizes! Anyway RHP are now owned by NSK.

When I was doing basic research on rolling element bearings in the 70's and
80's the general consensus was that there was little to choose between the
big names (SKF, NSK/RHP, and FAG). Timken specialise in big case-hardened
taper rollers typically used in the "tough" end of the market.

There is a massive mark up on bearings. Employees were entitled to 60%
discount on deep groove and 40% on tapers.

Care is needed when fitting replacements as simply whacking them in with a
steel hammer is likely to cause damage.

Agreed on both counts