yes, it looks gorgeous, but the only clear advantage is accessibility and the elimination of that trek to the shop. bottom line, you're still going to spring for the device and the app, regardless of whether you are going to pay for some sort of subscription, or (cough, cough) otherwise. what happens if your iPad suddenly explodes? do you have any rights to the comics you already purchased? am sure it will be a physical file inside the device - it would be stupid for it to be stored online and claim you "own" it.
its a nice shiny toy, and it would be awesome to be reading comics with it. long-term for the voracious reader/collector, its too early.
plus, all those signature hogs/collectors who have no goal except to profit from the books via eBay (you know who you are), won't have anything tangible to have the creators sign on now, would they?