Buy the extra large size and buy a divider to use while the puppy is growing (using the divider will cause less problems while housebreaking the pup.) It is more cheaper too.
Opinions on this tend to vary. The way I see it, is that the risks of leaving a dog uncrated are much higher than any downsides of crating. You can be assured that while your dog is home alone in the crate, it's not going to get into trouble or possibly injure itself. It depends on how confident you feel letting your dog wandering around freely inside your home.
Good luck with your new puppy