Their lowest rate is 4.08%...I know because I've just switched to it.
This is the best offer around.
Having read a bit about it since my last post I see that the lowest ltv interest rate is 4.1 whereas NIB is 4. What criteria did you use to get 4.08?
The APR is 4.08%. Try the LTV calculator on NIB's website.
Generally APR is the best way to compare rates as it's uniform.
What's the difference between apr and interest rates? Did you have to change your current accoun to NIB too and how much do they charge for fees?