Manual and electronic shuffle machines you can find at a store are easily exploitable, providing a false sense of security for anyone who thinks they mix the cards thoroughly.
I recommend not using one of these machines for any of your games unless you understand how the cards are being shuffled.
Considering most people may only run the cards through a machine like this once or twice, they are opening themselves up to a number of exploits including shuffle tracking large groups of cards and top stocks being retained.
