I have the cat's meow. I like it a lot. i went backpacking, it got wet, (Feet pressed against the side of the tent) and the insulation warmed it right up, and I didn't even realize it until to morning. It is also mad light for a synthetic bag. Mountain hardware also has a synthetic sleeping bag with Polargard 3D. form what i hear, it is also very good.
The fit of the bag is good, it has plenty of room for your shoulders, and I can easily put on a pair of pants and change my underwear without leaving the bag. The temp rating on the cats meow is also right on. it is good until 20 degrees F, but after that, its pretty chilly.
If buying from an actual store, I would reccomend actually getting in the bag in the store to make sure it fits. A bag that is too short or tight will be uncomfotable, and a bag that is too big will not be as warm since you have more space to heat.
just a few things to think about. Personally, I like the cats meow a lot. if there was one thing i didn't like is that the lining gets smelly quickly. After a week of camping without showering, I smelled horrible, and so did my bag, and even after airing it out, on the next trip, the bag smelled horrible. I think that an anti-stink lining is in order. However, I'm sure that this is common on other bags, I just noticed it especially with this one.