Like most jobs it comes down to what your circumstances are and what you want from the job. Personally as a new FO I think it's a great job. Many airlines, particularly lo-cost, charge for the type rating, whether they ask for the cash up front or take it from your salary when on line so nothing out of the ordinary there. I can't speak for Captain's but understand that the package may not match up so shop around if you feel there is better for you elsewhere. What you'll get at Jet2 is a company that owns all of it's aircraft, has a very successful business model and most of all has a good bunch of crews keen to help the airline succeed. Make your own choice.
Jet2