Many things need to be factored to find the right low light scope for yourself, but if just talking glass, then the S&B Polar is indeed at the top of the heap. I've found nothing better.
With that being said, and the fact you have $1300 set aside right now, I'd take a hard look at the Minox All-Rounder. It comes very close to the Polar in performance, has the option of setting the illumination to a darker curve (you'll want to do that) and affords resolution that rivals anything out there. The All-Rounder is the culmination of improving and streamlining/simplifying the excellent ZE5i series. The series hasn't been heavily marketed but is definitely worth a look.
Right now, Optics Trade EU from Slovenia has them in stock, and with shipping/customs fees, the 2.5-10x50 will run you just over $1300. The 3-15x56 is about $80 bucks more. Don't worry about int'l shipping; it's quicker than ground here in the US lol. A scope I recently bought from them arrived in 3 business days.
Here is a link:
Minox page at Optics Trade EUThere are a number of other excellent optics that would serve your purpose. But sadly, a number of them -- like the Kahles Helia scopes -- can't be purchased here any longer and can't be imported, either. Hunting in Europe is often a low-light activity, and scopes available there often vary greatly compared to what is served up to the US market. The Steiner Ranger 4 and 6 (not sold here but can be imported) are perfect examples when compared to the Steiner models sold here in the US, all of which have far too bright of illumination and reticles which aren't the best for low light applications.
