I don't shoot as much as I used to but if you can fit a big objective lens on your rifle, that is the way to go for low light, IMO. I prefer zooms so that I can use low powers at dusk and high-power at long range.

I have found nice glass in Nikon, Leupold and Swarovski consistently. I have found some bargains from old model Bushnell and Tasco, too. I went out on a limb and bought an SWFA Super Sniper about ten years ago. One of the clearest scopes I had ever handled.