More secure than using your actual card, since it uses tokenization and virtual cards. That means that the actual card information the vendor is getting is only good for that transaction alone. Even if their databases get hacked and they get your info, they can't do anything with it because it's no longer valid for new transactions.
Only problem with Android Pay is that you MAY have issues getting certain card offers if the bank's system isn't optimized (transactions show up as ANDROID PAY followed by the vendor you used it in, so some banks have issues automatically recognizing a purchase in some vendors because of the Android Pay prefix, but it's not so common and you can simply call them to make an offer valid).