So, which one will become the summer jam record, perfect for blasting at slumber parties and Forever 21 sales? The good news for the artists is that the world of teen pop is a magnanimous one. Fans are encouraged to listen to all the competitors; nary a beef is in sight. Sparks might be the 'Idol' alumna, but it's Lovato who's most influenced by Kelly Clarkson's style. Even the title of Lovato's '80s-inspired 'Remember December' could be taken as a vote for Clarkson's maligned full-length 'My December.' On the title track, Lovato tells a guy where to stick it over buff guitar lines, a la 'Since U Been Gone,' Clarkson's gold standard in kiss-off rock. For the bulk of the album, Lovato channels a witty, pouty ingenue in high heels who's not afraid to call the shots, especially after a good cry. When she breaks from her 'Sex and the City' act for Mouse-loving millennials, the 16-year-old shows refreshing versatility. On 'Falling Over Me,' her vocals balance delicacy and force. The lifting of a phrase from Cyndi Lauper's 'Time After Time' is a nice touch, a signal that Lovato is reverent of all the chart-toppers who have gone before her, even the ones with the Technicolor tresses that surely would violate a Disney contract. Although her album is not as consistent as 'Here We Go Again,' it might be Sparks who will generate more hits from 'Battlefield,' which was written in four months, unlike her rushed self-titled debut. The 19-year-old doesn't have the kind of actorly chops that Lovato uses to embody character, but Sparks does have the pipes -- earthy, full and transcendent. 'Battlefield' is a bid for recognition as an adult with her own mind, and it offers some positive signs. The title track, cooked up in part by OneRepublic's Ryan Tedder, ends with an exhilarating, if bombastic, call to 'get your armor.' 'Watch You Go' is one of the best offerings, an impeccable collaboration with T-Pain and Dr. Luke that shows Sparks' natural proclivities toward lovelorn R&B. But the album lags in its second half with songs that feel half-baked and are not aided by clever production. Many were penned by Sparks, whose writing abilities are far from hopeless; they simply need more development. It turns out that forging her independence is also a battlefield -- as much with herself as with anyone else. Jordin Sparks 'Battlefield' (19 Recordings/Jive Records) 2 1/2 stars Demi Lovato 'Here We Go Again' (Hollywood Records) 3 stars Album scale: one star (poor) to four (excellent). 