Originally Posted by Chris_W

I agree that in terms of shifting performance, an electronic RD isn't that much different than a mechanical RD. However, if you run a non-stock cassette than the electronic RD will cope with it far better than a mechanical RD. Also, having an electronic RD gives the option of having a gear display, which is very handy on a tandem. Finally, having an electronic RD gives the option of having shift buttons in multiple locations, which is something that suits me well.