Crystal 10L is a sweeter, almost carmelly tasting, malt. Crystal 80L is more toffee-ish, not quite raisiny. There is a big difference in flavor, BUT both are great in IPAs and I don't think it'll change the overall tone of the beer that much where you will notice a lack of sweetness in the finished beer.
Broken Leg Brewery
Giving beer a leg to stand on since 2006