Walgreen (NASDAQ:WBA) reported a slight miss on bottom line earnings this week, prompting general unhappiness about the company's sluggish growth as it (and competitor Rite Aid, which also recently reported) deals with drug reimbursement pressure that is eroding margins.

But there are some silver linings for Walgreen investors -- synergies with Alliance Boots appear likely to come in ahead of previous estimates (judging by management raising expectations to nearly half a billion dollars for this fiscal year), and same-store sales increased smoothly, despite some decline in store traffic.

But Walgreen's most important silver lining is definitely the potential Alliance Boots acquisition -- and in the video below, health care analysts Michael Douglass and David Williamson lay out why investors should watch Walgreen's upcoming decision on the acquisition.