Crock-Pot® is a trademark name used by Rival. Anything else is called a "slow cooker". Don't you just love attorneys.
The newer Rival products run HOT (on purpose), again thanks to their attorneys, and I would not recommend them for that reason. You get a slow cooker so it cooks SLOW, not boil food even on the low setting.
I personally recommend the Hamilton Beach brand of slow cooker and the size you get depends on your family that you are cooking for. I would love to get the 3-in-1 to give the best of all worlds, but I have to wait for present one to wear out and that doesn't look likely any time soon. For 1-2 people the 4-quart is a good size, otherwise go for a 5-quart or larger.