Some more clarity.
Security Bond Repayment: Not as good as it seems on paper.This is not paid on top of your salary, so year 2 in EJ for example (in the UK) you’re looking at around £40k/41k; and so the security bond will be repaid at £12k per year. Therefore, your £40k salary will drop to £28k and the security bond will top this up to the £40k. The slight advantage here is that the £12k is tax free, so instead of the tax free allowance of £11k, your tax free allowance would be around £23k.
Employment: If you get a UK base then you go on a CTC flexicrew contract for up to 3 years with the opportunity to become employed by EJ permanently. If you get a European base you become employed by EJ immediately…but you don’t get your security bond back. However, the salary is slightly higher (in most EU bases) and you get all of the employee benefits from the start.