If you're talking about the Snugpak one, I've got one, I use it as my warm weather sleeping option, I don't think that it would be something that I would want to depend on much beyond summer months from my experience, others experiences may vary.
I have one. Snugpak is like a U.K. Version of wiggys. Built tough but neither cutting edge tech nor light weight. I have used it a few times. Good to about 40-50 degrees but you may need a jacket too. That bug net was clutch once to ward off a cloud of mosquitoes in Canada. Apart from the bug net, I would say I prefer a quilt like a woobie for this summer time sleeper role.
Bug net is good but not perfect. If you end up with a hot night and bugs you either sweat in the bag or open it up and get eaten. Hard to explain, but basically if it is cool enough to want even a light mummy bag, mosquitoes are going to be less of an issue.