Well I own both of the devices you are asking about.
Personally I would get the Prodigy. It is the most adaptable device on the market. (with exception to the GG). You can get an extra switch with the resistor (it comes standard with a resistor that limits the two 3.0v
batteries to 5v, Sweet spot) this switch without resistor will give you the exact same experience as the Silver Bullet being you could put a 18650 2500 mAh 3.7 volt battery in that will last you for a few days... or use the two rcr123s for a 6v vape. I have every option and I personally like the 3.7v big battery with the 510 atomizer. The flavor and vapor are perfect for some reason.
Now if you want huge clouds of heavy warm vapor go with the 801 at 6v. There are some juices that are ok at this voltage like nHaler's High Voltage line.
Personally I really like how many choices you have with the Prodigy. Adaptors can be purchased to use whatever atomizer you want. (the 510 is by far the best one out of the bunch) and being able to use the device at 3.7v, 5v, or 6v is just great.
Now the Silver Bullet is a nice PV don't get me wrong. It sure is pretty and shinny, BUT it is much bigger and heavier than the Prodigy. I personally don't like the feel of it in my pocket. It would be great to have in a bar fight...lol... And it is a heavy duty device. I could probably drive my car over it and not hurt it one bit. THe Prodigy is also a very nice looking device just a bit lighter and smaller in the hand and pocket.
After using both for a few weeks now (just got the Sliver bullet) and the Prodigy I have had for over a month now. I wish I would have just saved my cash and stayed with the Prodigy. I might be selling the SB soon. Just cause I don't use it other than at home.
The other plus it the Prodigy will be a lot easier to get your hands on. The SB is made in smaller production runs. I think the Prodigy is in stock at the moment and you would get it in a few days.
I am just much happier with the Prodigy now that I have the switch without resistor and a few of the 18650
batteries. They are 3.7v but they seem to really be much stronger than a standard e-cig battery. And they last much much longer. And if I want a different experience I can always throw in the switch with resistor and two 3v batts for the perfect 5v blast. They call it the sweet spot for a reason. The
juice doesn't burn like it does at 6v. If you want to run 6v you will need to get special juices.
Anyway, hope this helps you out. If you are truly dead set on the Silver bullet make me an offer on mine. lol.... But I hope you will go with the Prodigy. I love mine.