As of Enyo 2.5 you can no longer set selected programmatically and then get the value of the currently selected option. It does, however, work if you set it manually, but if set programmatically after that it will return the value of the last manual selection.
Here's some fiddles:
enyo 2.2.0 http://jsfiddle.net/sbk2t8k4/ — works
enyo 2.4.0 http://jsfiddle.net/z91jm5w5/ — works
enyo 2.5.1 http://jsfiddle.net/nrh04uj3/ — broken
enyo nightly http://jsfiddle.net/bsqg9n18/ — broken