Gundam Build Fighters seems to be nearly universally well received, but if you're not a fan of the kid audience focused bits of Gundam franchise like BF and AGE, there's Gundam Thunderbolt, an older audience seinen manga running in Big Comic Superior from Moonlight Mile author Yasuo Ohtagaki. With tie-in models out this month, Bandai has put together a promo.
Set in Universal Century 0079, Thunderbolt follows the fierce battle between in Federation and Zeon, namely Io Flemming and sniper Daryl Lorenz, taking place in a hazardous shoal zone composed of the debris of destroyed space colonies.
Gunpla kits include
GM (Gundam Thunderbolt Ver.) (HG)
Zaku II + Big Gun (Gundam Thunderbolt Ver.) (HG)
Full Armor Gundam (Gundam Thunderbolt Ver.) (HG)