Which Learjet is it? Learjet is FAR25 which is good and your hours count towards unfrozen ATPL and you may even unfreeze it as a Copilot after reaching 1500 hrs total time. 3-4 Years for a bond sounds quite alot and 3 weeks on/1 week off is also a very demanding schedule (is it standby at home or away for an owner at some base which is not at home?). Salary ok? Many questions to answer but from my feeling I would rather take it then wait for something better to come up. Try Ryanair too because they now pay the rating with a bond and offer professional training, as well as good career options (quick command, base in Portugal or Spain). Good luck!