Vortex 8.5x50s are perfect IMO, but I havent used them extensively.

Same size/weight as alot of 8x42/10x42s, but 100x better during lowlight. I also like the lesser power of 8.5 than my dads 10x and 12x binocs.

50mm lets in more light, thus being able to see better in darker situations. Difference between them and 42mm are neglible in 99% of situations though IMO.