From a marketing point of view, you can offer consumers a seamless brand experience without having to depend on a salesperson. You can even post a QR Code that automatically generates a Facebook "like" for your product or service whenever the code is scanned.
QR vs. SMS
As a generalization, QR Code responses differ from SMS text responses in the way lead generation differs from a one-step sale.
A text response to an advertisement is usually offer-driven. It's a quick way to help close a sale. Text responses can be used for mobile coupons, for example. Or responders can be directed to a website, mobile site, quiz session or toll-free number.
QR Codes often lead responders to a richer experience of the brand. They are another way to start a conversation with the consumer.
A big advantage of offering an SMS response right now is the prevalence of feature phones over smartphones. Many smartphone users also aren't aware of, and therefore aren't using, QR Codes yet.
On the other hand, SMS marketing may be a more expensive proposition when you include the costs of registering and maintaining a short code and paying for messaging.
QR Codes Aren't For Everyone
Some people won't have the software needed to utilize QR Codes. That's why, whenever possible, you should also include a printed URL in your marketing material, so the site can be found without a QR Code reader. The point isn't to look so cool that only those in the know can find you—the point is to actually be found and to bring the consumer a little closer to buying.
As with traditional direct marketing, your marketing will be most successful when the consumer's experience aligns with expectations. A QR Code ought to lead to a very specific mobile site that answers immediate questions, shows a brief video or creates some fun for the user.