Seantheman - to get the max 'best buys' interest the money must be left for the full 3 or 5.5 year term. The point I am making is, with Saving Bonds and Saving Certs, money is not locked in and can be withdrawn anytime without penalty.
Fungus - Saving Bonds 3 year rate is slightly higher. For example, €1,000 invested in Saving Bonds is worth €1,100 after 3 years, €1,000 invested in Saving Certs is worth €1,080 after 3 years. If a saver can leave money on deposit for 3 years but no longer Bonds are better (average interest rate of 3.23% DIRT free per annum). If a saver can leave money on deposit for 5.5 years Certs are better (average interest rate of 3.53% DIRT free per annum).