Silver Bullet, non variable voltage, is a different class than the Buzz Pro or Provari. I'm a big VV fan, though right now I'm actually vaping on a really beautifully crafted 3.7V bottom feeder.
Infinity Pro from notcigs would get you the same performance as the Buzz Pro for a bit less. If you don't already have a charger, I'd recommend either two or three sets of batteries plus charger.
With notcigs, their M1A1 tank is $10 off if bought at the same time as an Inifinity or Buzz. Also, for notcigs ue their "ECF Buzzkill" (2 words) discount code.
Provari is also rightfully popular. I've stayed with notcigs because I like how they run, but if you want an LCD interface the provari is a good PV. Alternately, also LCD but a good chunk lower cost (and lower performance/build quality from what I've heard) is the Lavatube -- many firms now carry variants of it. I'd take an Infinity Pro over an LT any day, high quality, rugged, voltage doesn't sag as the batteries deplete, but appreciate that the LT is affordable.