At CTIA Wireless 2012, venerable point-of-sale equipment maker VeriFone officially launched SAIL, its prime mobile payments system for retailers. The whole system seems uncannily familiar to Square, including how the mobile card reader plugs into smartphones via the 3.5mm headphone socket and lets merchants process card swiped transactions effortlessly. Additionally, the card reader can work in conjunction with static VeriFone countertop card readers and NFC technology. To see how an entire payment is processed through SAIL, check out our hands-on video below.

Merchants using SAIL will have two tiers of payment options available to them out of the gate: a flat fee of 2.7% for retailers who don't expect to use the mobile card reader that much, or 1.95% with a $9.95 monthly subscription for higher-level merchants.

On mobile devices, VeriFone's SAIL apps contain the standard-issue management system that details all the merchant's transactions, inventory, etc. Once a sale goes through, a user also gets quick access to social features — to review a store they've just conducted business with, for example — via Yelp, Facebook and Twitter shortcuts baked right into the app. 

Finally, the company stressed that the SAIL app would remain open so developers can work with the API to create new promotions (like coupons and loyalty discounts) on the platform. SAIL is free to download from the iTunes Store today, with an Android version landing in Google Play later this month.

Square certainly has the advantage of being out in the market for much longer, but as an alternative, SAIL presents some pretty attractive features. The system is multi-device, boasts an open API, and includes a social network aspect for merchants to build closer relationships with their customers. Whether Square will remain on top in the coming months remains to be seen, but it's quite clear that they've now got some formidable new competition.