As long as you are working and paying tax it is worthwhile to pay into a pension and you are allowed to do so
I would recommend that you take out a PRSA as you will have greater retirement benefits this includes the tax free lump sum you mentioned. However you are only allowed to take out a tax free lump sum of 25% of the total fund value, the remainder must be used to either buy an annuity, ARF or taken as a taxable lump sum.
This is only the best option if your new employer is not going to be offering you access to a pension scheme.
You should also ask your new employer to contribute to your PRSA as they will be making an employers PRSI saving on any contributions you make even if they do not contribute