You'll get lots of varied answers to this question and everyone will tell you why they love the machine they have. I have a Big Shot and I love how versitle it is.
You can use it with every die out there, with one exception. The largest die in the set of the Grand Nesties.
You can use embossing folders from various manufacturers.
It can cut through more than just paper and cardstock, too. You can cut fabric, veneer, plastic, cork, sponge, chipboard and more!
Its a great machine whether you're looking to make layouts or cards or gifts or tags or home decor etc.
This site has a comparison chart. I'll see if I can find it and link it for you. Do your research and pick the one that is right for you.
Enjoy whichever one you decide on!