Bought for my 4year old daughter, who loves it. With a bid of decoration (we have wrapped some gentle fairy lights round the apex) we've created a bed that my she is excited about getting into, makes bedtime much easier. It's turned the bed into a feature in the room rather than just a functional piece of furniture.
It is very comfortable (we chose the top mattress) and is low enough to the floor that it doesn't matter if my daughter rolls out of bed during the night - in fact she hasn't woken up!
In terms of building it - all the parts were clearly labelled and it went up all together in around 40mins.
My wife and i were a little concerned that the kids may be tempted to hang off the horizontals, but after explaining this risk of damaging the bed this hasn't been an issue. Although the horizontals do make lifting a sleeping child into the bed quite difficult - i hit my head several times initially, but quickly learned to avoid that!
Great bed.