Marvel, on the other hand, are charging $5/month to read everything that they've made available in digital format. Which frankly would be enough to get me to hand them my cash. Except that that's an offer that's only available on the PC/Mac. If you want it on a tablet then you're out of luck. I've read comics on a 10" tablet, and I've read comics on a 22" monitor, and frankly I'd rather read them on the tablet.
And, of course, everything is wrapped up in proprietary formats - in fact, both Marvel and DC have outsourced their iPad/Android comics to Comixology. Buying in software/expertise is one thing, creating a monopoly you're dependent on to sell your comics is quite another.
2000AD is slightly better - all of their issues are available in the standard CBR format (and PDF). And some of their trade paperbacks are too. However, not many of them are, and crucially there's no way to tell what is available, you have to trawl through their entire shop until you bump into something with a "Add Digital Copy" button underneath it. Of which there isn't that much. The first Judge Dredd trade was released that way a couple of years ago, but nothing more has been added since.
This all seems like rather a wasted opportunity, to be honest.
Original post on Dreamwidth - there are comments there.