If you are looking for a dedicated machine for business card scanning, there are quite a few to choose from. I did a quick google search and came up with a nice-looking article that compares some of them. The main feature you are looking for as far as MRSware-compatibility is the ability to output the contact list that it creates as a spreadsheet. Once in spreadsheet form, you can use the normal MRSware Contact Import Wizard to import the list -- you can even assign the list one or more Categories in MRSware at the time of import, say if they were all from a particular trade show, for example.
Pretty much all of the machines support exporting the contacts to Excel, so you don't have to worry about this feature requirement much. And, of course, most of them support inputing the contacts into Outlook; and you can synchronize Outlook with MRSware very easily.
However, I will say that dedicated machines for this are definitely on the way out. What has already replaced it for a lot of people is using one of many available apps for your cell phone, which uses the phone's camera to scan and import the contact information. This works in a similar way as the hardware scanner on your desk does -- point your phone at the business card, take a picture, the app then recognizes the text and inputs it as a contact. You would then just synchronize your phone with MRSware (which you may already be setup and doing).
While Goggle's is free, there are also a number of apps that your could pay for. The main one I see as far as popularity is CamCard (iOS, Android, Blackberry, and Windows). There are a couple of reasons to invest in a more-dedicated business card scanning app, such as: group card scanning, to get multiple cards input more quickly; export to excel; and merge with existing contacts features.
In addition to exporting to spreadsheet for import, or synchronizing directly with MRSware, all of the mobile devices will be able to email out vCards of the contacts as well. vCard is one of those standard formats for contacts (iCal / vCal is the equivalent for appointments) that any MRSware User can open and save directly in MRSware.
I hope this information helps, and I am always interested to hear what people are using -- if you find something that works great for you, let me know.