I'm wondering if anyone here has chosen so sign with any of the digital distribution labels that Tunecore has helped put together for the major labels?

They are:

Interscope: Interscope Digital Distribution: Digital Music Distribution
Republic: Republic Digital Distribution: Digital Music Distribution
Island DefJam: Island Def Jam Digital Distribution: Digital Music Distribution
Motown: UniMo Digital Distribution: Digital Music Distribution

Any positives/negatives? Have the labels offered you any opportunities/resources?

This is a very new thing so I just wanted to open up a dialogue about it and hopefully hear about some user experiences.