A 6-24 sounds like you're thinking about a Crossfire line model? Vortex has a great, no questions asked transferable warranty, but as they themselves will admit, the lower priced Crossfire line constitutes a good deal of their returns. They can be really great scopes for the price, but quality isn't as consistent as the Diamondback, Viper and premium Razor lines from the reviews I've read.
I've shot a Crossfire on a .22 AR. It has very nice glass for its price range. Adjustments seemed roughly on, but that was at 50yds and under, so not too much of a test. It held zero just fine of course.
My Viper 6.5-20x44 is easily the best scope I own. I bought it in preference to a Nikon Monarch 5-20x44 model. Its glass is on par with my dad's Bushnell 4200 Elite, which is a nice scope in its own right. It tracks well out to 300yards.