The most value for the dollar is at 3-9X40 regardless of who makes it. I've found that decent quality starts at about $200 MSRP. If you can find something discounted below $200 great. But I'd not buy anything under $200 MSRP. Once you get above about $300 the quality comes in smaller steps and at bigger price points. A $500 scope is only slightly better than a $300 scope, but a $300 scope is going to be far, far better than a $150 scope. For hunting there are a lot of $200 scopes that I'd not feel the least bit handicapped with. I prefer some in the $300-$400 range, but that is more personal preference than anything else. At about $200 the Burris FF-II is my default recommendation. But there are other good choices. And Leupold is never a bad choice.
When it comes to objective size 40mm is about as big as anyone needs. The typical human eye can only use about 5mm of light coming through the rear of a scope. Any less and the scope is hard to use in low light, much more and the human eye simply can't use it and it is wasted. That is calculated by dividing the front objective size by the scopes magnification. A 40mm scope lets 5mm of light though at 8X. Exactly the same as a 50mm scope at 10X or a 20 mm scope at 4X. A 20mm scope lets in exactly the same amount of usable light as one with a 50mm front objective depending on the magnification used. What the larger objectives do is allow you to use more magnification. On lower magnifications bigger scopes do let in more light. A 50mm objective at 3X lets almost 17mm exit the rear of the scope. But most human eyes can't use more than 5mm so it is wasted.
If you go above 10X even with a 50mm objective you'll get poor results in low light. The only time a scope with a 50mm objective is better in low light compared to a 40mm objective is if you have the scope set on 9X. Any more, or less magnification and exactly the same amount of usable light comes through. I've killed deer 25 minutes before sunup with 20mm scopes. Legal shooting time is 30 minutes prior. I'm only aware of one state, SC, where it is legal to shoot 1 hour before and after sunrise/sunset.