I mean, it depends on your other Pokemon and what you want from the Pokemon on that exact spot. Empoleon is a (very) good utility mon, it can be a Stealth Rock setter, a Defogger, it has access to Knock Off and Roar to cripple stallers and phaze set-up sweepers, and in Mono-Steel, it helps not getting completely abused by Fire mons.
Typhlosion on the other hand is much faster (and actually has a decent speed tier) has access to Eruption, which like Swampellow said, benefits greatly from many Field Effects and can change them, but also to Nature Power (and he's actually the only non-Grass starter Pokemon able to learn it).