Mr Buffett, widely known as the world's most successful 'value' investor (buying companies when they're cheap) has bet heavily on Apple this year. Sounds like a great opportunity, right? Well, opposite more likely to be true. Most investors should beware the 42% rise in apple stock this last 12-18 months and watch out for the time old mistake of buying high (based on sentiment caused by press coverage like this) and ultimately selling low.