Talonflame is primarily a revenge killer, and is the best revenge killer in the meta, however there are a number of threats it is unreliable at RKing: Sand Rush Excadrill, DD X-zard/Gyaraod/T-Tar, Kabutops, boosted Mawile/Bisharp, Aegislash, Dragonite, SD Lucario, CroCune, CroMana, and many others.
Furthermore, Talonflame has a quad weakness to sneaky pebbles and low bulk, so only rarely is it able to put its actually fairly useful defensive typing to use. This pebbles weakness, and its reliance on recoil moves, means it is generally short-lived.
Talonflame also has a set number of counters that can handle every good set it can run; Heatran, Tyranitar, Rotom-W, Mandibuzz, Slowbro, Hippowdon, Mega Aerodactyl, Rhyperior, rock types in general, phys def Gliscor, Quagsire, etc. Talonflame can only change its counters around with the gimmicky Natural Gift set, which reduces its overall effectiveness, or the TauntBU set, which only works against the stallier of its counters. Talonflame also has a very large number of checks, these checks generally being electric types or just bulky attackers in general.
tl;dr Talonflame is a fast, frail physical attacker that is countered and checked fairly easily, and has a very short lifespan. Git fucking gud, and not in the "learn to live with stupid bullshit like Mega Mom and Luke," I mean "learn to live with something that has 81 base fucking attack."
