This is a very good sofa bed.
I didn't realise that there was some assembly required, which was a pain as we needed it for that same night, but that was my bad for not reading the spec properly before ordering. It took us 2 hours to assemble - no idea if this is an average assembly time for this item, probably not as I absolutely hate self-assembly as it's not my bag!
It is very firm, both as a sofa and as a sofa bed but because of that it should be pretty durable. I would say it's probably more comfortable as a sofa rather than a sofa bed but hey, for the quality and price it's pretty good. We had a camping mattress which we added on top to make it more comfortable to sleep on.
We had a small space available for this and it fitted perfectly, although I would say when using it as a sofa you can still quite easily seat two people on it without having to sit on each other's laps.
It is pretty easy to transform and the mechanism seems pretty sturdy.
I'm giving it 5 stars.