Remember that you can get up to 48% (42% tax and 6% PRSI/health levy) relief on a pension contribution so a contribution of €5K to your pension could only cost you just over €2,500 once you claim relief.
On the basis of the information that you have posted so far I see no compelling reason why BES is for you but it really depends on your overall situation and probably only an independent, professional advisor who does a detailed review/fact find can help you.