If an optic works, it works.
I've intentionally abused optics to see if they will fail and my Tasco's seem to have lasted pretty well. I put a Tasco on my 7.62mm K98k Mauser a million years ago when it was an inexpensive project gun and it's still on there. It's held up and it still holds it's zero after a zillion rounds. If it ain't broke, don't fix it.
I've also got a 4x40mm Tasco with an illuminated reticle on a 10/22 and that thing has taken all sorts of critters.
BUT, I will admit that my Tascos are old and before Bushnell took them over. I know that back in the 1980's, Tascos had good glass but plastic innards, so a lot of guys would intentionally get Tascos, knock them loose on the insides, and send them in for warranty, where the plastic innards got replaced with brass. Then you had a pretty good scope.
I've found out over the years that it doesn't always have to have a Leopold or a Swarovski label (or price tag) to perform, especially with the newer scopes. I know of some .50BMG shooters that have found out the same thing, much to their surprise.
You can also break any optic if you try hard enough, Swarovski or Tasco. For my Mauser and for my CAR-15 I keep spare, identical optics around as an emergency replacement for the one on the rifle (that would get a tad pricey with a Swarovski). So far the originals have held up through a lot of abuse.
Don't get me wrong, Swarovski optics and thier ilk do kick ass. I like them, and I plan on mounting one on my 6.5x55mm rifle project.
Nowadays, with modern, computer controlled machinery, optics are coming into the country from places with cheesy reps, like China, that are surprisingly good. I've got a couple of Chinese made optics that are holding up like champs, a BSA red dot and a pair of Carson 6x16mm autofocusing mini-binos. The BSA is only $30 and doesn't weigh much at all, just toss a spare unit in your ruck in case the one on your primary weapon takes a sh!t or maybe catches a fragment or the like.