I always buy a new mattress when I buy a new bed, and this is one of my favourite ones I've had over the years. At around £585-£600 depending on where it's bought from, it's a bit pricey but definitely worth the money as it's comfortable, stays firm after lots of use and has a 5 year guarantee.
Silentnight is a reputable brand, and the Belle Cirrus Memory Foam range is designed with comfort and back protection in mind. It's one of the better brands out there and I 100% recommend it as both mattresses I have had from it have been wonderful and ever supportive of my dodgy back!
The comfort of this mattress is just perfect for me personally although it has potential to be unsuitable for different types of people depending on your preferences. It's comfortable and does have a bit of bounce in it, but is a medium firm mattress and supportive of your joints when lying on it also. It's comfy but firm and doesn't tend to shrink with wear either - it's quite a 'tall' mattress.
It fits fantastically with a correctly sized double bed frame and doesn't appear too wide or bulgy, and this is handy especially if you have your bed at the wall as I do.
Silentnight describe this mattress as allergy free - meaning it contains no materials which are physically able to trigger allergic reactions. This is a very good aspect but I have no allergies so thankfully have never had to learn the hard way about this.
It's a very comfortable mattress but won't suit anyone. I highly recommend it to anyone with money to spend on a reputable brand to ensure comfort!