1. How does the card stand on its own? Is it good, bad, or has potential? Is it worth playing.
I find Lanturn to be quite good on its own actually. Even though it is weak to a fighting type Pokemon like Donphan, Lanturn's Poke-power let's you turn into a water type, thus allowing you to literally counter an incoming Donphan Prime. The fact Lanturn can turn into water also makes him great with Feraligatr Prime. Here, you can turn Lanturn water so that it can take in the water energies from Rain Dance.
Now we get to the attack, which is really why I think it is good. It can hit for 40 plus 10 for every energy on all of your Pokemon. Even though Feraligatr helps here, with DCE, Lanturn can attack just as awesome as it can with Feraligatr. After all, the fact DCE provides two energies means that it can hit for a load of damage. Overall, Lanturn is pretty good on its own, has potential, and it worth playing.
2. What popular metagame decks is it used in?
There aren't many decks in the metagame that use Lanturn right now. If Lanturn were to see competitive play, it would most likely be played with Feraligatr at this moment, or even on its own. Yet, I have seen a Lanturn deck that won Juniors in a Battle Road against a Luxchomp. That deck was Lanturn Prime/Electivire FB. Here, you use Lanturn to attack a lot, and when your DCEs go into the discard, you use Electivire FB Lv.X's Poke-power to grab those DCEs out of the discard and back onto your Lanturns. Believe, I think that when played with Electivire FB, Lanturn can be good in the metagame that way; of course, that is, if Lanturn can do a real good job.
3. What combos can you use it with? How so?
Other than the Electivire FB combo that has been previously mentioned, I would run Lanturn with Feraligatr, combo wise. As mentioned, I would turn Lanturn into a water type via its Poke-power. Then, I would use Rain Dance to attach energies like crazy to all the Lanturns. This can be effective, but the problem with this combo is that it greatly suffers from power lock. Yet, in most cases, I wouldn't just prefer playing it with Feraligatr. At the same time, I kind of would also like to try running Lanturn in a straight fashion. That is, it would pretty much be a speed Lanturn deck. Well, either way, I would play Lanturn with comboes and without it. It doesn't seem to matter with me whenever I look at this card.
4. Give it a rating, and explain why you would give it that rating.
I would rate Lanturn Prime a 4/5. Lanturn is definitely not a bad card. It has a good Poke-power that let's it hit through its most common weakness, Donphan. It also has a very good attack that can potentially hit for very high damage. Lanturn can be good either with another card or on its own. Yet, its main problems include that not so good retreat cost, and the fact is can be overwhelmed by other very popular decks in this very moment. Regardless, Lanturn is one good card all right.
5. How's the artwork?
I think this is an awesome artwork for a Lanturn card. Both Lanturn and the dark background behind it really add a great feel of a true Lanturn. Hideaki Hadozaki really did a great job designing the art.