Perform Down Bag -7C

Definitely a good deal, but I'd be a little worried about temperature regulation when using it on warmer nights since it's your only bag. The opening style is super conducive to pocking a leg out or opening the bag slightly to cool off. Looking on the REI website all the reviews of it come from expertvoice, which is a website where people who work in the outdoor industry get discounts on gear, so the 4.8 stars is definitely inflated. Having worked at an outdoor store (not REI) in the past, and used expert voice, the ratings from reviews on there are not reliable. So definitely do a little research beyond those reviews, I'm not saying it's bad, just that those reviews aren't super reliable. Obligatory note about temperature ratings since you say this is your first bag: All temperature ratings are based on the assumption that you are wearing socks, long underwear, and a long sleeve base layer top, and sleeping on a pad with an R-value of 5. The 19F/-7C temperature rating is the limit rating. The limit rating is the temperature at which a typical man will be temperature stable in the fetal position. The bag's comfort rating is 30F/-1C is the temperature at which a typical woman will be temperature stable while laying flat on their back.

I doubt they will have the Mammut bag to try out. They don't carry their stuff in stores much, but it's a great bag. You can always have it shipped to the store or your house then return it with tags on if it doesn't work for you. The beauty of REI reurns

Well yea they will have sleeping bags, but they don't carry much of Mammut in store. It's a euro brand and more popular with the mountaineering community than the camping community. That was my point.

Not correct. I borrowed one of these sleepingbags and my life isforever changed. It follows your body like a glove, like the front zipper is always at the front no matter where and how or how much you turn. It was amazing. So this sleepingbag is amazing for side sleepers!