I shoot long range on a weekly basis, but it depends on what your definition of long range is. To me long range is past 800 yards with most guns. I like to shoot between 900-2100 yds the most. The zoom ability on the scope has a little bit of effect on hitting targets, you need enough zoom to clearly place your shot on the target with the reticule, not just see the target. This all depends on your target as well. Yotes for an example, I do some serious varmint hunting and I can tell you that the more zoom you have (for distance) can make all the difference, however the bigger deal is the quality and clarity of the glass and more importantly the coatings on the glass. Parallax adjustment is a critical piece on a long range scope as well. Being able to adjust the parallax helps huge amounts on placing shots at long range. If you're shooting long range often, an exposed turret of some sort isn't required, but it sure does make it faster, easier, and nicer to run the turrets. If you're just a hold over shooter, then thats not a huge concern for you. Personally I own Vortex, Leupold(everything from a Vx-III to Mk6), Nightforce, and U.S. Optics, I do also have a smitt and bender but never use it, not a fan. In my honest opinion, the Vortex is the best optic on the market dollar for dollar and flat out, both my Viper's PST (1 FFP, and 1 SFP) are better than my Nightforce NXS on all aspects. I also run a Vortex Viper HS LR on my go-to varmint rig and it's a GREAT optic, everything you need to shoot long range. It's a 4-16x50, which for my tastes is a bit weak on max zoom, I prefer a 20x or greater, but again I place my shots, if I miss my point by more than 6" at 900 yds I'm ****ed. Being able to see and place 6" at 900 is hard to do with a standard style and reticule hunting scope (duplex of some sort). The price point on the Vortex's are great too. Don't shop around too much, Vortex prices are on MAP, so the price is going to be same every where you go. The 4-16x50 HS LR should run around $540, you can get the same scope without the turrets and reticule for around $450 as well. You can spend $2000 on a scope from Viper, but there's really no need in my opinion, their middle of the road Vipers will provide you with anything you need.
I've played the cheap optic game before, and it's bit me in the *** every time, learn from me if you can on that.
Vortex should pay me I swear, I sell a lot of their scopes after people shoot mine and play with it.