Ventajas
Interesting projects to work on and plenty of autonomy. These are the only positive aspects I can think of.
Desventajas
Extremely unprofessional and stingy attitude of management and HR. They only offer the legal minimum of holiday allowance (20 days) and pension plan (1% employer contribution) and the salary is on the low side as well for the location (London). Moreover, they would look for any pretext to cut back on even these limited benefits. I was promised a pay raise following the completion of an initial 3 month probationary period. After the agreed 3 months have passed they have conjured up some bogus reason to unilaterally extend my probation, just so they would not have to give me the raise we have agreed on when I accepted their employment offer. To make things worse, when I left the company, they didn't even pay me my full salary. I tried to contact them for clarifications, but they did not bother to answer.