Lightweight summer synthetic sleeping bag

[Dragonflypsu]

I am planning an AT thru-hike starting this spring. I have a winter (20 degree) bag that I am planning on using in the beginning and end of the hike. However, I need a lightweight summer bag. These are the ones I am currently considering:

Mountain Hardwear UltraLamina 45 Synthetic

Sierra Designs Wicked Hot 45 Eco synthetic

Lafuma Extreme 650 Pro 40 degree

Does anyone have experience with any of these bags or have suggestions for another one that I should look at?

Thanks

[skinewmexico]

I've seen some great deals on LaFumas on STP, under 2# and $40. I'd get a 30 degree though, it will be closer to a 40.

[johnnyblisters]

My Lafuma 650 was on sale for >$30 last summer on REI outlet. Awesome summer bag, about 1# and stuffs to the size of a nalgene. Granted its not the warmest (~45*) and only for summer use (or as a heavy duty winter liner).