Marmot - Col Sleeping Bag

Im totally with you. Sleeping bags are way too personal to be rented. I used my Marmot Col -20 for Kili and it was great. Someone above mentioned condensation - I had this issue once on the trail and realized it was because I was stuffing my bag before letting it cool off. On all subsequent mornings, I got out of the bag, opened all zippers, and let it cool off for about 10min before stuffing and had no more issues with condensation.

It's got 38oz of 800FP. I'd say that's good for about -20F or so.  I have a marmot col -20F with a similar amount of down and I was sweating in it with heavy base layers at -7F. 

I bought mine for $500 on sale. There are always sales at the end of winter. But yeah this is pretty equivalent in amount of down. However, the baffling system, draft tubes, and hood seem better on the col. I would guess this is probably 6-7 degrees colder than the col. 

Quilts, semi rectangular bags (Sea to Summit Trek and Ascent Down) or the Big Agnes Sidewinder series are what you want. The Nemo Spoon series of down bags are also quite roomy. I sleep on my side. I use Hammock Gear Econ Borrows most of the time and I have a Marmot Col -20F bag for anything 20F and below.

Years ago my wife and I got 2 marmot mummy bags. One with a zipper on the left, the other on the right. We still have them and they work great together. Plus they work independently for solo trips

Marmot is a solid brand, like the other commentor said its a personal choice. I would invest in the Marmot down fill bag myself and thats based on the longevity and utility of all my other Marmot purchases.