This question could make for an awesome sci-fi story premise. Seriously.

On-topic, second life. At first, an infinite lucid dream would sound nice. But what about after a year? After ten years? After a century? There will be no contact with another life form. You have to spend eternity in solitude. Think - how maddening could that become? Sure, the DCs would provide some company at first, but what happens when the novelty wears off? What happens when the person sees and does the same things, over and over? What happens when the person loses their sanity, craves the affection of others, craves to see at least one more person like themselves again - but never can? Living in an eternal lucid dream might eventually become an eternal lucid nightmare: one that only gets worse... and worse... and worse... and worse... and yet the dreamer will never awake from it. And thus, they will fall into deeper loneliness, deeper loss, deeper insanity.

So, second life for me. :B