Investment returns uncovered

What's the difference between the best funds and the worst funds available ?
The short-term
Well, over the last three years, the best fund has returned over 77.4% and the worst has returned -6.3%. That's a difference of over 83.7% in just three years.
The long-term
If you're looking at a longer term investment, this kind of difference can make a huge difference in value. The FTSE 100 went down from 5142.10 to 4040.90 over the same time period - that's a drop of over 21%. Over five years, the difference between the best fund and the worst fund is 149.7% and -11.3%. That's a total difference of 160%. The FTSE 100 has gone down by around 5% from 4240.20 to 4040.90 in the same time period.
These investment figures were quoted from Fidelity's website on 23rd October 2008, and we haven't even included the figures from the Life Assurance Companies!
It doesn't matter what type of contract you are in i.e. ISAs, Investment Bonds, OEICs (updated Unit Trusts) or Pensions, we can now invest these contracts in all the same choice of funds.
So, arguing that pensions aren't as good ISAs or an OEICs no longer applies because they each can be invested in similar funds with equal chance of performance.