A few months ago, McDonald's spent $300 million to make its biggest acquisition in years, a tech company called Dynamic Yield. 

Company executives described its "personalization and decision logic technology" as a key part of their vision for the McDonald's of tomorrow.

So far, so good. The technology is about offering customers exactly the food items McDonald's wants to push at any given moment, literally changing the menu in real time from one customer to the next.

Except that as The Wall Street Journal reported on Wednesday, some customers at McDonald's and elsewhere say they're bothered by the kinds of digital menus that come with the technology: too many choices, and not enough time to read and absorb them.

One former McDonald's manager said that before he left McDonald's last November, "one of the most common complaints was that the menu was confusing because these big sweeping animations would show up over the menu advertising new sandwiches."

As an example, when McDonald's ran a promotion for The Lion King movie, "entire McDonald's menus began periodically transforming into widescreen, animated vistas of the African savanna," reports the Journal, "flanked by advertisements for movie-based Happy Meal toys and Walt Disney World vacation lotteries."

The Dynamic Yield technology is intriguing, especially for tracking and personalization: following customers by their use of the McDonald's app, and the in-store kiosks, and maybe even tracking license plates.

"When you serve 68 million customers every single day," McDonald's CEO Steve Easterbrook said in a March press release, "our ability to learn of their behaviors and play that back through this technology is unbeatable. It gives us a huge competitive advantage."

When the weather changes, or the line at the drive through gets backed up, for example, McDonald's can quickly change its menu boards to promote cold drinks or faster-prep items, for example.

Now, three points. First, McDonald's isn't alone. The Journal story cites similar experiences at Regal Cinemas and Wendy's, and points out that restaurants first started using these kinds of digital menus in the 1990s.

Second, the customer concern isn't with Dynamic Yield specifically; it's with moving digital menus in general. McDonald's said in July that it soon planned to use Dynamic Yield in 8,000 locations.

Second, the menus -- and the rollout that McDonald's has given Dynamic Yield so far -- seem to work from a business perspective. 

Finally, the menus seem to work from a business perspective. Digital menu boards at quick-service restaurants generally bump up sales between 3 and 5 percent, according to a study cited by the Journal.

Easterbrook said on a July earnings call that McDonald's is "already seeing an increase in average check," from using Dynamic Yield, although the company didn't give statistics.

End result: Even though this is the kind of thing that would have blown audiences away in a science fiction movie just a few years ago, it's likely coming soon to a McDonald's near you.