I am considering pulling the trigger on the Mountain Hard Wear Lamina Z torch 5 degree synthetic bag. Anyone have experience with this bag? Are the temp ratings highly overrated? Durability? Sizing? Zippers? Reasons to shy away or dive in? I signed up for the constant emails and they have tossed a 15% discount out there, so for around 180 bucks after discount it appears to be a good deal if the bag is quality. Comments? Thoughts?