First it's important to note that Ripple is not a currency, it's a global payment network that costs virtually nothing to use. Within this payment network you can use any currency you choose. USD, EUR, YEN, BTC, LTC, PPC or any other currency there is liquidity for. I say this because it's important to know what you're investing in. It's not Bitcoin. It's a true protocol like http, not a single crypto currency.
Is Ripple actually gaining any traction as a payment network?
I've yet to see a single business accepting XRP or payment through Ripple network, or hear about any major/regular transaction going through it..
Are there any stats about this out there?
It's not, and it shouldn't.
It is closed-source, centralized, has a currency called XRP that is 100% premined and in the hands of the creators, and the whole thing is owned by a for-profit company.