1. How does the card stand on its own? Is it good, bad, or have potential? Is it worth being played?
It's a little hard to play it by itself unless you Rainbow Energy it for the damage counter it places to activate the Body, but it's not worth even that because you're better off attaching 2 DCEs to use its final attack (two turns of energy attachments as oppose to three). In the short run, it might be okay to do a Rainbow Energy and a DCE, but in the long run, you simply waste an energy turn if you plan on using the 2nd attack. 120 for two energy CARDS with no drawback is very big (140 with expert belt, but it may not even be worth it with Crobat G to provide a power boost when needed without exposing an extra prize for the opponent). Nasty fighting weakness means that Donphan will eat this guy for lunch in a single gulp with Earthquake un-Expert Belted. Retreat Cost of three doesn't help, but I guess with a power-based card, it's reasonable for balance.
2. What popular metagame decks is it used in?
Neither of the following is currently popular by competitive means, but both have huge potential come the MD-on format. The more commonly seen one is Typhlosion Prime/Ursaring Prime/Ninetales. Use Ninetales' Roast Reveal power to discard your fire energy, then use Typhlosion Prime's Afterburner power to attach that fire energy from the dicard pile and, due to Afterburner's "drawback," place a damage counter on it to activate Berserk, the main point of all of this. You only need to play one DCE on Ursaring because of the energy acceleration provided by this, too.
The other deck it can easily be used in is one that is strangely overlooked: Donphan Prime/Ursaring Prime. Donphan Prime is used as the early game attacker with Earthquake for one energy. Aside from amazing donking abilities, Earthquake's normally annoying effect of doing 10 damage to your benched pokemon can be abused rather easily for the purpose of getting the damage counter on your Teddiursa/Ursaring Prime very early in the game, thus activating Berserk. Then while Donphan is causing havoc, drop a couple DCEs on Ursaring Prime and it's ready to... well... go berserk. You can then either let Donphan live out its spotlight in the active slot until it dies, or since they both share UGLY retreat Costs, play a Warp Point or Switch to switch out and start pwning with Ursaring Prime. With them both being stage ones, only, this allows room for such cards in the deck. Either way, it puts a LOT pressure on the opponent much earlier in the game with the massive early damage it's swinging out. This is a varient that I believe will gain more popularity when people starting thinking of after worlds. Some may actually use it.
3. What combos can you use it with? How so?
Read above. Anything that places damage counter on it works well. Typhlosion Prime and Donphan Prime are the most notable ones. Rainbow Energy is okay, but not worth it in the long run due to an eventually wasted energy attachment. Unown P from MD is also note-worthy, but most players won't justify a bench space for this when there's ways of abusing other pokemon's drawbacks like Donphan Prime's Earthquake for damage counter placement.
4. Give it a rating, and explain why you have given it that rating. You can also rate the card by rating the thread itself (out of 5 stars).
4/5 I personally believe that it's a bit underrated right now. While it's true that Ursaring only has 100 HP after activating Berserk, Donphan Prime and Ursaring Prime together just scream for major early-game damage. HP doesn't really matter too much if you're set up before your oppoent and dishing out 60 per turn by turn 2 and 90-140 by turn 3, and retreat cost always has a work-around via trainer cards like Switch and Warp Point, which would naturally be in such a deck. I believe that in the coming format, It will start to shine as more people realize its potential. Just watch out for other Donphan Primes laying in wait.
5. How's the artwork?
Personally, I'm not an Ursaring fan. I find this bear pokemon ugly, but this doesn't concern my opinion of how I think of a pokemon's looks, right? The art depicted in this card is truely epic, as with all the primes. No detail wasoverlooked, and I've constantly been in love with the 3D effect all the Primes get. This is no exception. 5/5