Back when I was juicing, I read that it's not a good idea to drink pure beet juice. Something about it causing constriction of the throat.
I also don't think it would be very drinkable (and even if it didn't cause constriction of the throat, it would have you in the bathroon more than you'd like to be!).
I used to make a combo of carrot, celery, beet and sometimes garlic (a small amount!). (Not as tasty as the carrot/pineapple/winesap apple mix, but not bad).
If you really are into beet juice, I think it's best to juice it yourself.