Vaadin Portlets compatibility


i want to develop some portlets for Liferay using Vaadin.

Now I am wondering if these portlets could be reused in other portal systems, like i.e. Oracle Webcenter (if i stick to the JSR 286 specification)?

Does anyone have expierences in using Vaadin Portlets on other portal systems than Liferay? How much is the migration effort?

Any hint would be appreciated.