Rating: 5 / 5
I agree --- the summerlite is excellent. I frankly don't trust any individual evaluation of a sleeping bag temperature rating (32F in this case); so many things affect this, including not only the general metabolism of the person evaluating it, but their metabolism at the time of their subjective evaluation (certainly I include myself in this). I use the Summerlite on two trips last year totally 250 miles, and felt that it did a great job of keeping me warm relative to its weight. I used it on one trip in a hammock, which is why I chose this model --- it was the best option I could find that had a full-length zipper, which allowed me to open it up and use it as a comforter. I used it in another trip with my wife in a tent, and it's a great mummy bag too; on the colder nights I can zip the (normal sized) bag completely shut (just part of my face showing) and it fits my 5' 10" (1.78 metre) long body perfectly with out being too tight but with just zero excess.
I do have a scale; in its small black 12" x 6" stuff sack it weighs 577 grams, or 20.4 oz. Again, I have the normal --- supposed to be for someone up to 6' 0" --- bag.
So I think the manufacturer's specs are slightly optimistic; it's supposed to weigh 19 oz, though the stuff sack is likely part of the difference there (and if they put in a little more down, that idea doesn't break my heart!). I think a 6' tall person would be okay with my bag, but would have to bend their knees a little if they wanted to totally zip into maximal mummy configuration. And since it's a 32 degree bag, that might be a little more common (plus adding extra clothes) if you want to push the limits a little in what conditions you take this bag out on.
My wife opted for the Ultralite bag, also by WM, also size regular. It's rated to 20 degrees and is definitely warmer --- and of course bulkier and heavier. The weight is further off spec here; the size regular is supposed to weigh 26 oz, but in the stuff sack I weigh it at 30.6 oz (868 grams).
I like her bag a lot in colder weather, but for a 10.2 oz weight penalty, I can carry a some extra clothing instead and wear that inside the summerlite, plus use it around camp.
If there's snow on the ground, I'd take her bag (and probably improved thermal padding ...), but for anything short of that I'm loving the warmth-for-weight and the full side zip of the Summerlite. I expect if it were a bit less expensive, more people would love it too ...