I am looking for a new 3 season bag. Trying to keep in the 1-1.5lbs range and 32-40degrees. I have three I am looking at but was wondering if there is anything else I should check out or what your thoughts are on these three: Western Mountaineering Caribou MF, Big Agnes Pitchpine SL, and the new REI Flash bag.

Matt, I can give you some feedback on the Big Agnes bag system, rather than that particular bag, so I hope this is helpful.

Since the BA bags are "quasi-quilt", meaning uninsulated on the lower side, but still a full envelope, you can get a bag that comes out pretty light since it relies upon your sleeping pad for under-side insulation. This does presume you carry a sleeping pad, and the BA bags will only sleeve a 20" or narrower.

One trade-off effect with the BA system is that if you "sit up in bed" (or the tent), the air mattress has to come with you. That was odd and took getting used to.

I use a Mystic SL, because it's light-ish and is cut wide. The lightweight zippers BA uses regularly jam. This is occasionally so annoying that I am known to remark "this is the last #$%@ time I use this bag" right after I have to swim an arm out and then burst the zipper to get out of my bag. The YKK's do self-repair (at least 10 times so far) and a new bag is expensive and I have a short memory... I suggest you visit an REI or other store and use the zippers from inside the bag, over and over. The larger zippers in a non-SL-series bag might not have any problem, and my wife's SL bag/finesse haven't had any jams. I'm just suggesting you check it out.

The pillow-sack inside the hood of the BA is handy. My down puffy lives there in warm weather.

Thanks for the feedback. I do have a Big Agnes Dual Core pad that I got a good deal on at a REI used gear sale and would be using it with any bag I go with. I am not normally a back sleeper and usually sleep on my stomach or side, not sure how well that works with the BA system. I am going to stop by REI today after work and check out their new Flash bag. It looks a little narrow at the bottom and that is a concern. I am 5' 10" and 230lbs and like a little wiggle room if possible.

I suggest the Western Mountaineering HighLite. It weighs one pound even and is conservatively rated to 35 degrees. I recently got one and, although I've only had it out a few nights, I can already tell it's warmer than my old Mountainsmith Wisp (rated to 30 degrees and six ounces heavier).

look @ both the Hydrogen (30F) and Atom (40F), fit/finish is excellent as are the materials (including the high loft down) and are lightweight- they can usually be found on sale for reasonable prices

I had looked at the Highlight but would like something with a full zipper so thats why I was looking at the Caribou same temp and only 4 oz more.

The Flash looks interesting, but is 1/2 pound more than my Mountain Hardwear Phantom 45. The Phantom 45 and the Flash are both rated at:
EN lower limit? (rating for men) 32 F
EN comfort? (rating for women) 41 F

I have slept in the Phantom at 18 F with one layer of warmish clothing and thick socks and been comfy. At 32 F I can sleep in it with no extra clothing. I sleep pretty warm though.

For those who either sleep cooler or need to accommodate much colder temps the Phantom also comes in a 32 and 20 model.

I love my Phantom.

Thanks for the feedback everyone. This gives me some more things to look into. Why do these decisions have to be so complicated to make?!?!

Are quilts out of the question? If not, I think quilts are much more comfortable than sleeping bags in addition to their weight savings. Jacks R Better and Enlightened Equipment make great quilts at pretty good prices.

Quilts are not completely out of the picture, but the ones I have looked at there isnt much of a weight or size difference in this temp range. I did go by REI at lunch today and checked out the Flash. Pretty nice bag and setup. I was a little concerned about the foot box and hip area, but after climbing into it the feel wasnt that bag, fairly snug, but still enough room to move around. With the dividend checks coming out next month and potentially the usual 20% off coupon and a few gift cards I still have from Christmas I might just go ahead and get this bag. It seems to fit all of my needs. Price, size, temp, and weight.

I would go with the Caribou over the Highlite. I have both and like the versatility of being able to unzip the Caribou all the way, it also has more room overall.

ZPacks makes hybrid quilt/bags that are 15.5 ounces in wide version with 30 degree rating:
ZPacks sleeping bags