McDonald's (NYSE:MCD) shares got a boost today after the fast-food purveyor said that March same-store sales sizzled. In addition, the company also increased its guidance for first-quarter earnings. This was definitely a quick recipe for some upbeat sentiment.

The purveyor of burgers, nuggets, and similar fast-food fare said that same-store sales for March increased 6.8%, which is especially impressive when you consider the fact that it faced tough comparisons to last year's strong sales performance -- when March sales increased 9.9%. For the first quarter, they rose 4.6%.

McDonald's also said that it's increasing its first-quarter per-share guidance to $0.56 per share, instead of the old consensus estimate, which looked for earnings of $0.43 per share. However, the new guidance includes a $0.13-per-share tax benefit and a $0.03-per-share expense related to share-based compensation.

The sizzling same-store sales provide an interesting contrast with Wendy's (NYSE:WEN), which reported lackluster same-store sales for March last week. At the time, I wondered about the possibility of an industrywide malaise in March, but that doesn't seem to be the case given the strength at McDonald's. Persistent investors of course want to look at other fast-food purveyors with a variety of quick fare such as Yum! Brands (NYSE:YUM) and Checkers (NASDAQ:CHKR).

When you compare McDonald's stellar performance to that of rivals such as Wendy's, you might wonder whether McDonald's could be a bargain at the moment. Earlier today, Fool contributor Mark Whistler took a look at the company's current valuation.

McDonald's performance is entirely impressive, especially considering the fact that it's been facing such tough comparisons to last year. While one might feel certain that it can't keep up such outstanding sales growth forever, it's clear that the fast food company continues its protracted turnaround -- and its continuing initiatives continue to win over customers on the run. This isn't the beaten-up McDonald's of yesteryear.

For more recent Foolishness on McDonald's, check out the following:

Alyce Lomax does not own shares of any of the companies mentioned.