Hi this is my first post and I hope im not posting it in the wrong forum

Its basically to ask if the BJ Blitz machines are worth playing. As I am fairly new to BJ, and dont want to go and play $10 a hand.

I have played the BJ blitz machines 3 times, first time broke even, second time doubled up and 3rd time lucked out
The third time seemed like a harsh hot streak for the "dealer" getting 21 almost everytime

Can anyone tell me if:
these machines are rigged, or if they hold the same advantage as a normal blackjack game would?
and If the machines can be beat?

Also would playing against 1 or 4 deacks make any difference?
I know the 1 deck shuffles after every hand.

Thanks in advance

-Cynic