If this "Commercially priced prevailing tracker rate" behaves like a traditional tracker rate, then I would probably avoid it, because the margin is so much over the ECB rate. The current ECB rate of 0.05% is at an all-time low. If and when (i.e. when) this rate goes up, your tracker rate would go up by a corresponding amount, e.g. by 0.25% to 3.97%. However, their other rates may not automatically go up by the same amount. This is because they are relatively high right now, compared to the base rate, so the bank could possibly afford to maintain them at current levels, even with an increase in the ECB rate.
As Rangemaster is inclined to fix long-term anyway, then 5 years look like the best option. Ulster Bank offer a 7 year fixed option though for as low as 3.60% though, and €1,500 towards switching fees, so that might be attractive.
I would also recommend shopping around for other options. If your property is not in negative equity, then there might be better deals out there. Many other banks are also offering cash incentives to entice switchers.
Best Regards,
Dave Curry, Irish Mortgage Corporation