1. How does the card stand on its own? Is it good, bad, or has potential? Is it worth playing?
Ninetales is not meant to be on its own, as essentially, it is supposed to be a support Pokemon for drawpower. The Poke-power is notably what gives it very good drawpower. You discard a fire energy from your hand, and then you draw 3 cards. This Poke-power is especially helpful in fire decks that's for sure. The attack? Well, 60 is decent damage, but the fact it needs 3 energies to use it isn't so satisfying. Thus, Ninetales is not that good on its own, but it has potential, and it is worth playing only in fire decks.
2. What popular metagame decks is it used in?
Notably, Ninetales is very popular with Charizard AR right now in our current metagame. Why? Well, Charizard AR increases damage for every fire Pokemon in play thanks to the Poke-body, so if you can set up some Ninetales and some Charizards, you can have a good way of dealing damage. Furthermore, Ninetales can help with drawpower so that Charizard can set up faster. Along with Typhlosion Prime to bring out the discarded fire energies from Ninetales (and Charizard) as well, Ninetales has found a way into our metagame, and it might even become better next year.
3. What combos can you use it with? How so?
Other than Charizard AR, Typhlosion Prime, as mentioned earlier, would be the one card I'd run Ninetales with. Typhlosion Prime helps bring out the fire energy discarded from the discard pile thanks to its Poke-power. In this way, you have the ability to reuse Ninetales's Poke-power in a more helpful way for almost every turn.
4. Give it a rating, and explain why you would give it that rating.
I would give Ninetales a 3.5/5. Ninetales has an excellent Poke-power that especially helps many fire decks greatly, namely Charizard AR and more recently, Magmortar UL. With the ability to discard fire, something like a Typhlosion Prime can help bring out discarded fire energies from Ninetales's Poke-power so you can really create a great of drawing out cards from your deck. However, the main reason why Ninetales isn't that good is because it isn't the best attacker, has a rather bad weakness, and the fact it only works in fire decks, not just any deck. Really, the fact the energy has to be fire limits its usages in other decks, so Ninetales isn't like Claydol for everyone.
5. How's the artwork?
I honestly think the artwork is epic. Notice how Ninetales literally "circles" that Fire Stone. The steam in the background really adds the feel of Ninetales that's for sure. I have to admit, this is a pretty cool artwork for Ninetales.