Data is generally sourced from the same places on both networks, but Witnet doesn’t use aggregators like CoinGecko, CoinMarketCap, or CryptoCompare like Band. This is because you must trust them to provide truthful information. Read more:

--Where is data sourced from?--

Band has parameters in place to protect against manipulation like generating seeds to select the next block proposers. However, it is worth it to note that delegating provides far less security than something like Witnet because delegators don’t run their own nodes.

Additionally, without a mechanism similar to Power similar to Witnet it is hard to predict how the network could centralize or decentralize.

If one delegates rather than staking on their own nodes, the coins that are delegated are in complete control of the delegatee and you must trust them to act in your interests. If you run a node, you are in full control of it and can act selfishly- the system is set up as such.

Band has a mechanism to choose validators from a pool of them. This pool is determined by the idea that a validator with more voting power (based on more staked) should be chosen more often, but still giving all validators a chance.