Which of these 2 summer sleeping bags?

I never consider a sleeping bag that cannot be ventillated well, ie full zip.

One's a quilt. The other a bag. Which do you prefer?

I think the Mountain Equipment Helium Solo is also a sleeping bag.

"I never consider a sleeping bag that cannot be ventillated well, ie full zip."

Agreed. Those aren't really "summer sleeping bags", they're adventure racing fast and light bags for people who are willing to sacrifice warmth and comfort for weight. Also neither are quilts clearly. But I would be much more inclined to go with a quilt like this: http://www.enlightenedequipment.com/product/revelation-40/

I was also thinking of a quilt but i have never used one before. My current sleeping bag is this one http://www.montbell.us/products/disp.php?cat_id=796&p_id=2321139 . What worries me is that my arms and head will be out of the quilt, not like the sleeping bag. I usually don't wear down jackets, usually a liner or very thin coolmax underwear.

I use this Montbell UL Down Hugger Thermal Sheet for my summer bag.

http://www.backcountrygear.com/montbell-ul-spiral-down-hugger-thermal-sheet-gunmetal.html?gclid=CLSlxYr3pLcCFScV7Aod9l0Aew

It's rated down to 50 degrees F, and I have had used it at that temp in just shorts and a t-shirt, and it's fine.

Mine's 13.8 ounces, and packs very small.

How is your sleep compared to your other sleeping bag?

My other bag is a Western Mountaineering Alpinlite 20*F bag. I use that in winter.

The Montbell Thermal Sheet is excellent.
I am 5'10" tall with very broad shoulders, and weighed 100 kilos when I got this bag, and I fit into it. It was a little tight, but I could do it. I have since lost weight and now weigh 85 kilos, and it feels real good now.

Here are some of the good points, as I see them.
1)Very light weight.
2)Very small packed/carry size.
3)The 50*F rating is spot-on, and with some clothing you could take it lower.
4)The hoodless design is a plus, in my opinion, because I don't want to be wearing a hood in the summer.
5)Full Zipper, and can open up like a quilt
6)Spiral hugger design hugs fairly tight to the body, so it can warm you up quickly in cooler weather.
7)Quality of the product is very good, in terms of construction quality. I like it.

In summer, I sleep on this with a Klymit X-Lite(6.5 ounces) inflatable 3/4-length pad, and it is very comfortable, and super light as a combination. About 20 ounces for the bag/pad combo.

I think it's a great item. I would buy one again.

Not technically the lightest but is a full featured "bag" . I have an EE summer quilt and its nice. I also have the NanoWave and I like it in the wind.
Has full mummy shape and weighs 24 ounces. Got mine for $56. For under tarp usage I like it since it covers head and has two zips so you can vent bottom.

My 2 cents……