Pyroar is another Lion-based Pokemon that was introduced in Generation VI, two generations later from when the Shinx line was introduced. Since there are so few Lion-based Pokemon, I thought it might be fun to do a comparison of both lines.
Luxio is part of the Shinx evolution chain which is 3 Pokemon in total. Pyroar, however, is just two. It begins with Litleo (which also uses the latin word for lion, like in Luxio's name) and ends with Pyroar. Unlike Luxio, Pyroar has significant gender differences as well. The male has a large, crested mane and the female has long, flowing hair that almost resembles a banner.
Pyroar are known as the Royal Pokemon. While Luxio is known for its strength and ferocity, Pyroar are made to resemble lions that you would see on Medieval flags or family crests. They also have the colors of red and gold associated with regal lions (also, Gryffindor). Pyroar's name comes from Py- as in pyro and roar. A name not as creative as Luxio but fairly straight forward, letting you know that Pyroar is a fire-type.
Pyroar, being a fully-evolved Pokemon, has higher base stats than Luxio. Which leads into my next topic: Which Pokemon would win in battle? I would, much to my chagrin, say Pyroar. It has the ability to learn more diverse moves, probably due to being half normal type, and could be taught moves that could easily take down a pure electric type. (Such as the ground-type move, Dig.) It also has stronger base stats: A special attack base of 109 versus Luxio's base of 60. (However, Luxio has a stronger base regular Attack stat of 85 versus 68.) Where Luxio is clearly stronger in Attack stats Pyroar excels in Special Attack, Speed, and Defense. Is Pyroar the more powerful of the two Lion-Pokemon? Well, maybe that depends on its trainer.