Pros
Great international atmosphere. Good work conditions, pay and benefits. Beautiful campus (used to be, don't know what it is now with all extensions.) Opportunities to attend many scientific conferences (much better than in most unioversities). I met some truly remarkable people at the EBI.
Cons
Career opportunities both within and after EBI are very limited. Normally you have to live after maximum of 9 years. For career and personal development sake, it is best to leave after 3 years but most people (like myself) take safe option to stay full 9 years, within whichI have progressed from a database curator to, well, senior database curator. This is a ridiculous job title and prospects finding a similar job which will pay at least on the same level are close to zero. There is a small (but, naturally, growing) number of people who are given rolling contracts. To justify that, the new group and team leader positions are constantly invented for no other good reason. The communication between different groups is very poor. The special international status of EMBL is a big problem for non-EU staff members. Normally, if you spend 4 years continuously working in the UK you are eligible for residency (indefinite leave to stay in the UK). However the time you work for the EBI does not count toward it and moreover, if you were previously employed in the UK for less than 4 years, you will have to start from zero after your gig at the EBI. Provided that you find a job in the UK, that is. So there is a real chance that after 9 years at the EBI (legally working in the UK!) you still will be forced to leave the country.