Michael Levy, a professor of marketing at Babson College in Wellesley, Mass., concurred. "They're both really good at marketing, they're very innovative, they do good marketing research, they try to find niche products, they've been at it a long time," he said. "We're dealing with two stellar companies here."

Historically, the companies are very similar — each more than a century old, each a pioneer in consumer products marketing.

More recently, however, both companies were in the same kind of fix and found the same way out. P&G's A.G. Lafley and Gillette's James Kilts both became CEOs at their companies within six months about four years ago. Both companies were drifting, and both CEOs turned the companies around by refocusing on the products that made them great. Both companies have grown in sales by about $5 billion since those CEOs took over.

But DeSanto noted that Gillette's Duracell battery line hasn't produced the same type of growth as the razors business. Likewise, the Braun line of electric razors, coffee makers and other small appliances might perform better with more support.

"That's a very competitive category (and) I think Braun's a great product," she said. "I think P&G's going to really be able to sharpen their pencil on that one and really get a lot more out of that. That's a division that Gillette doesn't have the resources to take where it needs to be."

Chris Allen, a professor of marketing at University of Cincinnati, said other recent P&G acquisitions looked more difficult on paper but have worked well so far. Wella, the German hair products company acquired in 2003, sells its products largely through salons. Iams, acquired in 1999, sold its pet foods through veterinarians and pet stores.

"In some cases, the folks at P&G have said 'that's a different kind of business ... and we're going to try to stay out of their way'," Allen said. "One of the things we've seen with P&G and their acquisitions is they really aren't forcing people's hand. When it makes sense to bring P&G's incredible scale to bear on an opportunity, they'll do it."

Gillette's managers should have no trouble adjusting to P&G's style of management, said Dan Dalton at Indiana University's Kelley School of Business. "P&G has been known perhaps to a fault for extreme levels of independence with its brands," he said. "My guess is the young men and women employed on the Gillette side will have a great deal of independence and discretion" to run their brands at P&G.

Allen said that compared to Wella and Iams, the Gillette acquisition looks easy. "Conceptually, these big Gillette brands should be easy to accommodate in the P&G model — same retailers, same advertising and promotion packets. I think it's going to be, at least on the surface, an easy thing to digest," Allen said. "If they can digest a Wella, who really has a different business model, if they can digest an organization like that and make it work within P&G, Gillette should be well within their capability."