Whilst I agree wholeheartedly with most of what Timeout says I have issue with one thing, that you are 'not really paying' for your training.
I guess that there has never been such a thing as a 100% sponsorship where you would not pay anything towards your training and then go straight onto a full first officer's salary. Of course, with the CTC scheme you don't go onto a full first officer's salary either. Typically, the reduced salary is 12000 pounds less per year than the full salary (coincidentally the same amount as the bond repayment from the airline).
Result: you've paid for your training with a bank loan, but are paying it back in a tax-efficient way.
I think I once calculated that during the first year with the airline if you were paying back the bank loan at the same rate (over 7 years) out of taxed salary you would have to earn 37000 to take home the same amount as a CTC cadet after the loan repayment.