Hi Boris, one of the real drawbacks of consulting si that the travel can be really unpredictable. For MBBB, expect to spend about 3 days a week on average working in a different country. You could have a project in London or be on the bench, then end up staffed on something that requires you to be in Dusseldorf for the next 5 months. You'll usually get to sleep in your own bed on Thurs, Fri, Sat and Sunday nights... but the travel WILL take its toll eventually. It's a very tough lifestyle, and is so unpredictable at junior levels that it makes any kind of family or regular social life very difficult indeed. You will basically be assimilated into "The Firm" and your social life will end up revolving around Friday night drinks trolleys outside meeting room 5.
For the 2nd tier firms, you're more likely to end up staffed in Halifax or Newcastle for 18 months, living out of a Holiday Inn and coming back home by train for the weekends. A grim existence indeed. But - at least you're still in the same country.
Personally I think the small firms are the best. You won't have a big brand name on the CV, but the work is more interesting, you learn more and get better experience, and you will probably have more control over where you work plus there will probably be quite a lot less travel too. Downside is also that they pay less. But at least you spend more time at home and have the evenings to yourself.
My overall advice is to remember that the hype of consulting rarely lives up to reality. It's tough work, with a tough lifestyle. The pay is better than most, although these days our clients tend to earn just as much as we do, if not more. Take everything you hear during the milkround recruitment events with a pinch of salt and base your decision on what you think you can sustain for the long term. Good luck!