Works well yes, but is very complicated for the normal user to set up. Check out Faustos post on Static Routing and prepaid Web Africa at
http://mybroadband.co.za/vb/showthread.php?t=52541 . He had found a way depending on what router you have to run both a local (IS) account and an international account at the same time and have local traffic sent through the IS account and international sent through his webafrica siax prepaid acc. Must easier than routesentry which is a great app but just complicated to set up.
Style
I haven't read through all the posts but from the look of it, it seems a hell of a lot more complicated.
RouteSentry is really very simple to setup.
1) Install RASPPPoE (just follow the instructions in the Readme)
2) Set the amount of WAN endpoints to two or more
3) Create a RasPPPoE dial up connection for each ISP account
4) Install RouteSentry
5) Select the international and local accounts in routesentry
6) Enable RouteSentry and Save Settings.
And that's it.