I bought my new summer bag, Haglöfs Goga 1S, since it's been reviewed very positively. Since the temperatures are still near 0 C, I haven't yet had chance to test it in real conditions. But the first impression is very positive. Images below show the old and new bags side to side.
Weight loss is significant, over a kilo. Volume loss is even larger thanks to the compression bag. Both are goose down bags, so Haglöfs will probably be clearly colder since it has less filling. But that's mostly positive, since I've often been sweating inside the Joutsen bag.
|Old||1875 g||19.1 L|
|New||835 g||4.6 L|
|Saving||-1040 g||-14.5 L|
An extra plus is that Haglöfs fits inside Joutsen, so using the two superimposed will give me a "super winter bag" if I'll ever need one.