I personally substitute a RIBZ pack for this layer)
How is the ribz? Is it hot in the summer (more specifically, how hot does it get in your neck of the woods and how do you handle the Ribz in the summer?)
There appears to be two sizes, 500 in^3 and 700 in^3. Aren't both sizes a bit BIG? What size do you have and do you find it rather large for the 10 essentials?