One thing to be aware of when considering the original: you have to monitor the box temperature yourself (requiring greater attention) or construct/purchase a PID temperature control device. The digital has some temp swing, as others have pointed out, but it really isn't much different than the temp swing in a normal oven. That said, you can set the temp target and be confident that your finished product will be good.
One quirk with the digital, though: for smoking projects that are longer than 9 hours 40 minutes, you will have to reset the timer before that amount of time lapses. I cannot figure out why Bradley would impose that limit on their digital model, but not the original. All the same, it doesn't take much to reset the timer and you can do so when you're basting your meat.
Good luck!