While Fools should generally take the opinion of Wall Street with a grain of salt, it's not a bad idea to take a closer look at particularly stock-shaking upgrades and downgrades -- just in case their reasoning behind the call makes sense.

What: Shares of Apple (AAPL 0.64%) gained 1% on Monday morning after Barclays upgraded the consumer electronics gorilla from equalweight to overweight.

So what: Along with the upgrade, analyst Ben Reitzes boosted his price target to $110 (from $95), representing about 15% worth of upside to Friday's close. So while contrarian traders might be turned off by Apple's year-to-date price strength, Reitzes' call could reflect a sense on Wall Street that its growth prospects still aren't fully baked into the valuation.

Now what: According to Barclays, Apple's risk/reward trade-off remains rather attractive at this point. "We believe Tim Cook has solidified his strategy and regained the confidence of Apple stakeholders in many ways -- reversing many of the warning signs we saw earlier in the year. Second, Samsung's weakness creates a large unforeseen buffer. Third, our checks around new products (builds, demand & quality) into 2015 are so strong, we are compelled to get on board even if its midway through the rebound trade," said Reitzes. When you couple that upbeat outlook with Apple's still-reasonable forward P/E of 13, it's tough to disagree with Barclays' bullishness.