I have to say, I have a number of them and have had no functional issues with any of them, some had poor glass or distortion, but they still held zero. I have a few guidelines I follow when I purchase any cheap scopes. If I feel the need to go against any of these, I buy something better.
1. I do not adjust the turrets once sighted, unless I change ammo and need to resight. If I am going to use it on a rifle I change ammo alot, or I need to adjust sight settings(like a silhouette rifle),I buy better. I do not trust them to be completely reliable if I am constantly cranking on them.
2. I set it to the power I will be using it, and leave it there. Alot of cheaper scopes seem to experience impact changes when changing power, so I simply set it and use it as a fixed power.
3. No hard kicking guns. If I have a heavy recoiler, I use better. I have seen a number of cheaper scopes fail on heavy kicking guns.
4. I wouldn't use one on a strictly target rifle I would expect extreme accuracy.
5. No high magnification variables. Most of the cheaper scopes I have seen lose alot of clarity at higher power.
6. If I had alot of money riding on a hunt, or my life on DG, I would own the best. I would not scrimp a few dollars that could cost me money or my life.
That being said, if I feel the need to break any of these, I buy better. But just because you spend more, does not mean a better scope. I have seen and owned bigger name scopes that I thought were unacceptable. The only one that I consider affordable(I don't consider $1000+ affordable), that I have never seen a poor one is Leupold. I am not a Leupold elitist like some(I do own 6 BSA scopes), but I have seen alot of them, and never a bad one from the clarity/brightness standpoint. All scopes can fail, I have witnessed more than one Leupold fail, it happens, much less in more expensive, higher quality scopes, but it still happens.
One last thing, I do not buy tham at normal retail prices. If I find a deal on them, I might buy one to try. If it looks good, I might buy another. I recently saw the 3-9x40 BSA Huntsman model at Natchez for $24.97, I bought one and it has been a decent scope for my Hornet. I set it and forget it. Works good enough, I bought 2 more. Your experience may differ, but for a low recoiling fun gun for varmints, it is more than adequate. I put one on my new OE .243, and it holds zero good so far, and I'm confident it will be fine for my local deer hunting.
I just wish someone would start making more affordable fixed power models other than 4x. I would love to just buy decent 6,10,12x fixed model scopes, without haveing to spend a ton. I guess I am in the minority and they don't sell that good, but some models like that, with decent glass, in the $80-$150 range would get my business for sure, but I guess I am one of a minority there. JMO, Billy