Looking to buy a new Queen Size mattress as my current one sucks and have been looking at brands such as Koala, Ecosa, Sleeping Duck, Macoda and Zzzatelier. However I've nailed it down to Eva and Sleep Republic. I found the other companies had too many mixed reviews and apparently some people were paid to write good reviews. I'm mainly a side sleeper and do suffer from shoulder and back pain.
Eva Mattress really entices me as it offers Pocket springs compared to Koala and Ecosa which are only foam. And apparently it keeps you cool in summer according to some reviews. The reviews also seem genuinely good, as I've watched youtube videos of a chiropractor reviewing the bed.
Sleep republic is really similar but a bit more expensive, but seems to also have genuine reviews.
IKEA. It's a mattress, you'll get used to it as it does to your body shape.
Other people's reviews, real or not, do not mean anything to your individual specific use case.