To start with the steelbook looks pretty cool, and it only costs a couple more pound the the plastic, so it's worth it.
What you get is MIB 1. Still a great film, and the transfer for the most part is very sharp. The odd bit of graining now and then but not much.
MIB 2. Looks great also as above, shame the movie was not quite as good as everyone expected.
MIB 3. Looks great and is a far better movie than the second one. Its what you would be hoping for in a MIB movie.
All the discs come with plenty of extras. So all in all you should not be dissapointed. Well worth getting, and remember. Always face it forwards!