We've used the offset since 2003, and it has worked really well. The facility (savings) account that sits beside the mortgage, benefits not only from any lump sum that you park there but from you salary lodgement, as the average balance in the facility account is deducted freom\the avg. bal in the loan account for calculating interest. Also First Active, don't seem to charge transaction fees on all of our direct debits . Your savings effectively get a return equivalent to the mortgage interst rate, which is higher than that available on any deposit account. First active only take your net mortgage repaymnet by dd from facility account and collect the TRS balance from the Govt. Their monthly summary is vey good and has improved since the First Active and Ulster Bank systems merged under Royal Bank of Scotland (not to be confused with Bank of Scotland Ireland). The online banking with F.A. is reasonably good, but for some raeson we cant set it up to pay AIB visa (MBNA Visa works fine). Our flaw with First Active is the customer services desk, and delays in setting up new direct debits, both of which have been frustrating in the past, but which now have improved.