Here is my thoughts on synthetic, which bear in mind may be wrong as I am a complete noob. I bought a kelty comsic mummy bag (first thing I bought) before I knew about hammocks and all I know is that it's way to freakin big. I am assuming that is due to the fact that it's synthetic this not compressing as well as down.

So with that if a synthetic uq is the same way I will have to pass on that.