It depends on the HP earned in the giveaway period. After the first Delegation Points will be credited (tomorrow), you can check the current possible APR here: https://splintertrends.com/delegation

I can't say the exact number. I think that the return will be greater than at other delegation services, just because the income is not only from votes.

If I were you, I would give it a try and wait for the end of the first Giveaway to check the numbers 😉