RE: Does holding DEC always give higher APR vs. Staking SPS?
Sorry just saw this now! Fully agree with all that @kotenoke said. Even with the higher DEC APR, I still prefer staking SPS because of the vouchers. The price range that people are willing to pay for it is quite high.
To add, if DEC's price continue to increase, DEC's APR will generally go lower. My expectation when this happens is that people with huge bags of DEC for airdrop will be "pushing and shoving" to convert their DEC to SPS. I'd rather hold onto SPS where the risk-reward is assymetric at this point.