I recommend Square's card reader. You can get the magstripe reader for free from Square. This should imply to you that most of their service is on the software side. They also advertise a contactless reader for NFC and chip cards as "coming soon", though you can reserve it for free. If you don't care about the "contactless" part, they have a reader that will read the new chip cards already available for $30.
I have had the magstripe reader for a few years. I use it for personal payments. It's supported every Android device I've had since the OS was version 2.0. It also supports my iPad and has run just fine through all OS upgrades in the last few years.
They have additional software related features you may find useful, though I can't vouch for any of those. These include a full PoS system, employee management, a market place and the ability to set up an online store through them.
Importantly, their rates are reasonable (for my limited use):
- Per swipe, sale on the Online store or Square Invoices: 2.75% (Swipe in $100, and you get $97.25)
- Per manually entered transaction: 3.5% + 15 cents (Enter $100 and you get $96.35)
Both methods accept Visa, Mastercard, Discover and American Express (with the same rates). Deposits go into your bank account within two business days.
As I said above, I use my Square reader for personal things. Usually payments among friends/family. I've also used it when hosting a garage sale. I feel that was very helpful in getting rid of more "stuff", compared to previous years where I didn't use the reader. Square will email a receipt to the customer and Square protects you for a small amount of charge backs (though, I have never used this feature).