The Primes have a lifetime warranty. Bushy will replace it with the new model if it fails. As to how tough they are, i dont know. My buddy has the scope I had, and still uses it often, spins the bdc, and bangs it around too, and its still going.
Optically I found it to be excellent, for a 50 dollar scope, more inline with the 150-200 dollar range, but again mine was an older version.