Bitcoin Core is the most secure you can go as it is most throughly tested by various developers and a lot of community members and it is a full node which doesn't require trust.
Bitcoins are the equivalent of Internet cash. You can send Bitcoins over the Internet directly to anyone with no middle man. Like cash, Bitcoin transactions are irreversible. Bitcoins are traded worldwide.
Bitcoin transaction can be reversed if a person controls over 51% of the network and they can easily reverse the transaction even with 6 confirmations.
I have zero desire to make another microwallet affiliated faucet; I think I'll just proceed and see what the balances look like on a daily or weekly basis and figure out the payout method based on that.
I know this is bitcoin talk, but I'd like to offer the choice of Bitcoin or a couple of alts. Primecoin, peercoin, what other ones are people interested in?
There are other services that work in similar ways that microwallet works but are competitors with microwallet (I believe one example is coinbox.me - however I cannot testify as to the trustworthyness of them nor of microwallet).
Anyone who would claim payments from a faucet that does not work with a microwallet like service is a sucker (then again so is anyone else that uses faucets) as they will likely need a very large amount of 'claims' - likely more then they would be interested in continuing to use faucets - before they can receive a payout
I think coinbox.me is broken. thats true, trusting your funds with a third party involves risk. Just do a batch transaction for those who reach a certain threshold, for example, when a batch of user reached 10k satoshi, send them all in one transaction.