Revel POS is a San Francisco-based start-up that launched their POS system in 2010. The system is Cloud-based, utilizes tablet-based cash registers, and is built to be flexible across industries: retail, restaurants, and more.
It's a fairly simple system that is budget-friendly when it comes to setting it up initially for a store. However, since it's built to be generic and flexible rather than specific to wine and spirits retail, there's an onus on a store to set up and manage important wine inventory attributes that aren't necessarily native to the system.
All that said, despite Revel only launching their software in 2010, their install base is massive across industries, and they're already at 200+ employees as a company. When compared to some of the other more recent tablet-based POS system start-ups, it has a pretty strong base.
Lastly, it's worth noting that Quickbooks POS is marketing a tablet-based version of their system, which is really a white-labeled version fo Revel POS. So if you're running the tablet version of Quickbooks POS, this is the right page for the details.