for a $300 difference
Brifters, a front and rear deraileur, rear cassette, extra chain ring...
a set of 105 brifters alone will cost you almost that much.
The big question is...what do you want to do? If you want to ride SS get one. if you want to ride geared - the felt is not a bad way to go.
You could also just go get a crosscheck or another versatile frame and build it up as a SS or geared.