Upload & Sell: On
Currently working on a card design ... premature thought, but I think I'd be more inclined to use it (larger) on the back of the card than the front (smaller/none), Depending on style of card, "four corners" could be interesting for graphic appeal, etc.
Also, likely would depend on your target market as to whether it would come across techno-savvy or unnecessarily gimmicky. Some would find it "way cool" ... but given the intent of the business card to serve as a calling card to facilitate remembrance/reference info, it leaves me to wonder it's lasting value.
If you've got the QR Code ... how are people going to use it, i.e. only with a reader. The QR code isn't something they can "remember" and use when they are away from their reader (or wherever they may have stored the code). I get that people are "attached" to their smart phones these days and wouldn't even consider taking their first morning's breathe of life without consulting it first. But, given the choice between using the (front) real estate for making an impression into their eye/brain/memory or having the QR code available for them to scan ... I'd likely opt against the QR code on the front.
But, that's just my "old school" thinking that I want to make an impression into their mind ... more so than their gizmo (but if they can't function without their gizmo).
There is a saying "Keep the main thing ... the main thing." Is the QR code stealing thunder from the main thing (diverting attention / stealing real estate) ... or is it adding convenience (really) and "techno-savvy" impression (really) that is going to help achieve the purpose you have for your card. There is only so much that the card can achieve ... is the QR code compromising the other aspects of the card?
To me, there is a certain amount of "depersonalization" that a QR code infers. Kinda contradictory (imo) if the card is part of the effort to aid them remembering you. If it is merely a lazy/convenience/cool tool/toy to let them avoid thinking/typing your website name, and that's what you want them to remember of you ... that you're "up with the times" and "techno-savvy" ... well, that again goes back to your target market and intent/purpose/expectation of your card, imo.
Personally ... I'm me ... not a number, not a gizmo graphic. If you can't put forth the effort to remember/type my name, than I must be of very little value to you. That, or I'm just something for you to "toy" with. Is that "bad on me" or "bad on you" ... debatable, but doesn't really matter ... it is "bad" in either case, imo.
Old school ... my .02.
Ooops, my bad ... you asked for the "popular view".
BTW ... here's a link to an image that I saw, just moments before reading this post. Take a look and think about your initial impression of the use of the code.