I've been pessimistic on Earth-like exo-planets recently; either as Mars-like worlds, that had their atmospheres stripped down, which is probably the case for most, "Earth-like", worlds orbiting a red-dwarf, or, they're Venus-like; if Earth never evolved photosynthesis, we'd have a thicker, methane-rich atmosphere that would be on the way to a Venus-like world by now (average temperature: 50°C).