I am a front sleeper and was looking for a firm mattress. Previous mattresses that were not firm enough caused me lower back ache and a stiff spine every morning.
This mattress, although classed as firm, did not prevent this back ache and stiff spine. I would class this mattress as medium and think it is more suited to side sleepers. Instead, I ended up switching to the Hyde & Sleep Original mattress which was also classed as firm, but the difference between the 2 is quite significant. The Hyde & Sleep Original mattress does prevent back ache and the stiff spine so I got there in the end!
I remember when trying out the various mattresses in the Dreams shop, the Hyde & Sleep Deluxe Ice mattress, classed as medium, felt firmer than the Hybrid Ice mattress which is classed as firm.