Does/has anyone use(d) a Big Agnes Iron Mountain matress?

They come in a family of matresses (mummy/rectangular and either long/short). Experience with any in the family would be helpful.

The reason I am asking is that I am a boney side sleeper who doesn't get a good night's sleep on the foam pads I've tried, and my other option is a 4lb Coleman airmatress (very comfortable, but too heavy).

I'm looking at buying this peice of gear as a warmer weather option.

Steadman