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No, what you are really asking for is who's the best - for the money. Rather than question the choice at all, which others will likely do, I'll focus on what you want them to do.
Flip ups are usually mounted on a scope/red dot flattop AR as back up sights, and not considered primary. Therefore, they can be the simplest design, should be rugged and lightweight, and since they won't be used enough to justify themselves, as low cost as possible. Mostly they need to stay out of the way, not snag on anything, and not get popped up when you don't need them.
If you're mag dumping four or five 30 rounders repeatedly, week ends on end, they will have to be metal. Slow fire, not so much, but Magpul won't cover any warranty on the MBUS mounted on the block. Steel is predominant, but the extra ounce of weight for it doesn't really get much - and moves the balance toward the muzzle. If it's mostly a bench or range gun, no problem.
A simple aluminum flipup would do fine, even an import. All it's going to do is mount up and stay down, so using some blue loctite on the screw threads will help that, and since they won't ever really be used in a life or death situation, I'd not spend one cent more than needed.
If I'm mistaken, and this is somehow an issue duty gun, then cowitnessed is the standard, but that gets back to what flipups really do - just lay there because "what if?"