Zero, why should I pay the same as for a physical copy, box, and manual, and only get an electronic ghost that I have to supply the memory storage for?
Not to mention that download games are a monopoly of the service (Big N or Sony) and are only usable at the whim of that service?
People who are confident that Big N and Sony will continue to support their games, might meditate on Sega. No one expected Nintendo's biggest competitor to dump their consolest and abandon their servers. Just try playing Phantasy Star Online on a Sega server now.
I'm waiting for Bandai to release the WonderSwan/SwanCrystal II and blow both the Vita and the 3DS away.