Just doing early fact-finding on Umbraco here.

We have a 3rd-party business system that has its own SQL database. We have a web site that interacts with this 3rd party system using archaic XML web services (that's all this 3rd party system has available).

The web application that we maintain sits within an iFrame on a sitecore front end at present. Each one of our members gets an account on our 3rd party system first and then scripts run to create the sitecore member accounts which the members use to log in to the sitecore front end and the authentication token is passed through to our web application in the iFrame so we can load their information from our 3rd party database. Once the member is logged in with Sitecore they also get access (depending on their membership level) to other services/3rd party apps that are embedded/linked to from the front end CMS.

Obviously we could do a straight swap with Umbraco for sitecore and embed our web application in an iFrame in the same way we're doing it now, but I'd like to consider the future.

We're considering rewriting our web application sometime soon. We will still have this same problem going forward though where we have different member databases with a requirement for a front end to hold them all together. I'm just wondering if Umbraco is going to offer us any great advantage over Sitecore (aside from cost, obviously!) in development terms as clearly we can't build umbraco forms for our members to maintain their details with that interface with XML web services can we? I'd have though that Umbraco forms would want to write data to the Umbraco database and then we'd need some way of maintaining the user data between different databases.