You really only have two choices Tony. Buy originals or don't. If the answer is no, I'll go with bearings that don't come direct from Toyota, what evaluation criteria can you actually use to determine which 'not' original ones to buy? Very few people have ever swapped wheel bearings on their 90s (on here any way) so I don't think there is sufficient body of evidence to be useful.
In my mind, bearings are such an involved thing to make, there'd be little point in making poor ones. It really would be like forging 1 pence pieces. Given that we tend to treat these things pretty badly by submerging them etc, how long would the benefit (if any) of OEM bearings last?
Get some bought and whack them in Tony.
Chris