It depends what you're doing at the IB's. Trading, Ops will let you get out on time every evening and you won't be working weekends whereas M&A, CorpFin will generally be longer hours than consulting.
Consulting has more opportunities to meet a wide range of people and travel around - i.e. the one-night stand recipe. Following the same pattern in the City can become messy because you see the same people every day. You'd be better pursuing drawn out, hothouse affairs if you joined IBanking.
Final consideration is that consulting has/attracts more attractive people than IBanking.