The other sacrifice is the size or thickness of the bag. A mummy sleeping bag essentially will certainly be much smaller sized for bring around which is why it is a preference for many backpackers/hikers. The rectangular resting bag isn't as small yet because it's not common to be lugging it, apart from somewhere in a vehicle while getting to your intended location, the bulkiness of the bag is not as large a problem.
The ideal way to pick a cozy enough bag is to go with one that handles a 10 degree colder climate than exactly what you're anticipating to be resting in. The last most significant consideration in selecting a bag is the insulation that is made use of in that bag.
When not utilizing your bag, never ever leave it inside a things bag, always hang it up or maintain it in a loose storage bag. In case you leave it saved inside a small bag, it can completely lower the insulation.