NEW YORK ( TheStreet) -- On the stock market, there is no shortage of growth stocks that are trading at high multiples. As a value investor, I often worry whether these stocks are worth the risk and can ever grow into their valuation. But also I wonder if investors will ever get the future returns they expect from paying such a premium today.This has been my chief concern with F5 ( FFIV). I've always wanted to like this stock but I could never collect the nerve to pull the trigger. On the heels of its most recent earnings report, I'm glad that I didn't.