I think the chances for the former are very, very small; the latter chance is slightly better (there could of course be some technical breakthrough), but let's say I wouldn't bet my life on that either...
Again, I'm no expert in these matters, and I'd be delighted to see some research that shows I'm overly pessimistic.
Of course, most cryonics advocates don't recommend having oneself cryonically preserved as an alternative to actually living one's life, merely as an alternative to having oneself burned to ash or buried in the dirt after one dies, both of which seem like even worse bets.
Having been diagnosed with cancer last year, writer Christopher Hitchens has died. He was known as as an outspoken atheist, which is not, in itself, identical to being a committed rationalist in any systematic way. Even so, he seemed to have the virtue of moral courage, the willingness to speak the truth as he saw it, without fear.