Hardware VPN's tend to be more reliable and faster because they are on a dedicated device. Once you setup a hardware VPN they very rarely need tweeking. Usually if the connection is dropped a reboot of the router brings it back.
Microsoft RRAS solution is a great one and works well in many situations but it tends to be a little slower because it relies on the server. It creates one more role your server is performing. And it relies on a server which probably has less reliability then a router. (I tend to have a server go down or need rebooting more then routers)
You'll find many sites talking about Hardware is better but much more expensive. True, you will spend more money if your current routers don't support VPN but most business routers do. They also talk about more difficult to setup but they truly aren't that hard. You'll find plenty of help on the settings and really if you make the settings equal on both ends then it's hard to go wrong.
I am not against RRAS as a solution but after using both I much prefer a hardware.
