I really liked the looks of the Snoozer but the price was a little steep for me -- I got my Pet Gear car seat for 1/2 the price and it works very well. It also uses the car seat belts to hold it in place and has 2 tethers (mine have never gotten tangled). The Snoozer looks like it might be a little deeper, which I would like, but mine have not fallen out or started going over the side of this one when we have been driving. So, I guess it is deep enough. It is very well made -- sturdy. The cover zips off for washing. It doubles as an extra bed when I have it in the house. They seem to really like it for a bed and definitely like it in the car so they can see out the window.
Pet Gear - PG11 - X - Booster Pet Car Seat in Charcoal | Pets By CSN This is the one I have -- can't remember where I bought mine, maybe Overstock.com -- it was close to $60. It was recently on a HUGE sale at the CSN site. I should have bought a second to just have a spare. But I moved too slow and the special pricing was gone before I could snatch one up. Still, this one seems to be wearing very well so I doubt I will need another any time soon.
I am sure you will be happy with the Snoozer -- I have never read anyone unhappy with that brand. But the Pet Gear is an affordable option that I am happy with too. Thought I'd give you something to think about.