They're all good brands. Holland and Barrett have been in business for 145 years. Perhaps your shop assistant isn't aware that all supplements are regulated for quality and ingredients. That is why the synthetic E has to say dl-alpha on the label. I stick with reputable companies when buying supplements. I've been using supplements for more than 40 years, so I am familiar with many of the brands, like Solgar. They stick around by manufacturing good products.
Yep, ignore his advice, mate.