The Leupold Mark IV is quite likely the best variable power scope available for use with medium power rifles. It will serve you well on an AR-15, an AR-10, a Remington 700, a Savage 10FP (mine is on a Savage 10FP), or any rifle of a low-medium caliber. The price may scare some people away but ultimately you get what you pay for and if you want a $40 dollar scope from China don't be surprised when it doesn't hold its zero, it doesn't hold up to even transportation let alone rugged use in the field, and it cannot be used except during periods of perfect sunlight. The Leupold Mark IV is worth every penny. It is easy to zero, it holds its zero, and once you have it zeroed where you want it, you lock the turrets down and then in theory [if you know the ballistic data of the ammunition] you could work your adjustments for different ranges and pretty much be on target, or at least wind up very close to where you want to be. The scope offers excellent possibilities for use in low light conditions, not pitch black but low light, such as around 8-9 pm in August when the sun starts to go down and there is still some light left in the sky, and the early morning hours around 5-6 am. The high quality optic really captures the light and provides a crisp and clear image. You can clearly read a headline text on a piece of paper at reasonable distances and you will be able to easily identify/discern your target because the image is just that crisp and clear, it is almost as though you are standing next to what you are aiming at. You shouldn't ever have to worry about mistaking something else for a deer, you'll know exactly what it is. For most people, myself included, the Leupold Mark IV offers more scope than they need. Presently the Leupold Mark IV can do everything I need it to do and it can provide more than I can use, although I aim (no pun intended) to change that through training and practice. I know that I have the right scope and that I will ultimately be able to fully realize all that this scope has to offer, and it has a lot to offer. It is a relatively expensive scope but it is the sort of scope that you only have to buy once. Stop going through numerous Chinese POS scopes every few years, just make the investment, buy a Leupold Mark IV, don't look back, and you'll never regret it. The most I have done is 500 yards but I know this scope will serve me well when I start to get out to 800 yards and beyond. The Leupold Mark IV will basically do whatever you need it to do and it is rugged enough that it will likely out-last you. Also, a bit of my personal opinion/perspective, based on having done some research into the matter, if you are just thinking about hunting then the front focal may not be what you need/want, but if you ever expect to get into serious competition shooting or if you are thinking about the possibility of major national distress/upheaval with possible tactical applications, the front focal may be what you want. Also, if you are going to go with front focal, go with mil-dot because there is no option for an illuminated reticle which means that the mil-dots are easier to see than the tactical milling hash lines/marks. However, if you are opting for rear focal, you may want to consider tactical milling as you will have the option of an illuminated reticle. Again, that's just my opinion on the matter, I did the research and decided that front focal with a mil-dot reticle was right for me.
Pros: Crisp and clear image, easy to zero, holds zero, captures light, suited for use in late evening and early morning, rugged, etc
Cons: Relatively expensive
This review was written in the old system and had content requirements that are different than reviews written today.