I was researching about DigStation myself when I came across your post so I thought I'd offer our recent digital distribution experiences.
We signed up with DigStation because it was included with the "MEGA" bundle upgrade we added to our Discmakers replication order--this basically included accounts at DigStation and CDBaby. I'm not sure if you're familiar, but CDBaby submits your album to iTunes, Amazon, Rhapsody, and a host of other places besides offering MP3 downloads on its own site. That said, the appeal of DigStation (from the artist perspective) is that 100% of the sales go to us whereas it seems 60% is the average on most sites, including iTunes.
We officially released our album and all digital downloads have been from iTunes, none from DigStation. I think the ubiquity, ease, and familiarity/security of iTunes make it the dominant and preferred choice--listeners trust it and they probably already have an account so it's convenient. In our experience, it was definitely worth having our music on iTunes so if you can get you music on there, it will probably be worth it.
What are the iTunes downsides? Apple takes significant percentage of sales (CDBaby takes an additional percent, but it is much smaller). On the other hand, if it lets listeners find our music who otherwise wouldn't, then it's worth it. It is also worth noting they pay the artist quarterly in case this bothers you.
I hope this helps, and good luck with your music!