Having used both, I prefer RTS. Yes, the annual licensing cost can be viewed as a yearly reminder that the system is costing you money. However, you get an outstanding support system for the investment. Emergency service is fast and helpful. They update their software very often, and you get those updates off the web. Also, there's more than one or two people behind the company... something that became a concern fairly quickly.
Some RTS users appear to gravitate toward keyboard operation, but I haven't found it to be very convenient, compared to operation over a touch screen. I use ELO screens, & have had as many as 12 of them going at one time... zero problems with them.
I'm also sold on the online credit card processing... 3-5 seconds and it's done. If you use the old card processors, you notice that right away.
RTS will switch between ticket and concession screens with one touch. You can also build multiple screens. We use separate screens at out drive-in for front counter sales, kitchen items and side orders. You can also build different screens where one terminal might sell something that another doesn't.
On the downside, RTS has some challenges keeping their help files up to date. That tends to get some of their users riled up some. I figure it's because they add features to the software so often, which I like. You can work around the help file issues by just calling them up. They don't mind helping you through anything you don't understand.
The system also requires registration in order to work. They do this during their business hours (remember, registration requires the annual fee). However, the support department can do an immediate 3-day registration for you so you can get running & contact the company during the day.
I'm in my 3rd year with RTS... can't see any reason to switch.