An attractive valuation, solid results, and improved guidance are the reasons why buying this tech stock looks like a no-brainer. Opera (OPRA -6.12%) may not be a household name among technology investors. The company is a bit-part player in the global web browser, search engine, and advertising markets, which are dominated by the big players. But the stock's recent action on the market following its latest quarterly report should warrant attention from investors looking to add a growth stock to their portf ...