Some people rave about them, but I can only conclude they have never used anything better, because they are a budget scope with lower performance then the equivalent Other branded models - or at least to my eyes anyway
I bought the £300 Discovery 5-25x50 HD version and it was ok for spinners on ranges, but just not clear enough when trying to focus on a paper targets. In comparison to the other scopes I use in this range - Aztec Emerald, Hawke Airmax/Endurance/Sidewinder it was simply not as well made or opticaly as sharp, but it was strangely clear and bright
Personaly I'll never have another, it felt cheap, and at that price point there are far better scopes for the money.
James