Eventhough my scopes magnify much higher than 18x I generally find myself somewhere in the 14-20x range even while shooting long. This power seems to lend itself well with a good sight picture to be comfortable and spot hits through the scope still. Although I've found this fits me well I still have yet to buy a scope in the lower magnification powers like the one you're considering. But I'd say if you're trying to go ultralight and 600ish yards is all you plan on shooting I don't see why the extra 8 ounces is worth it.