Litotes said:If comparing like with like, there should be very little difference, IMHO.
Each FTSE100 tracker will track the FTSE with an error that depends on how they have constructed and maintained their tracker. Those errors should be small - less than 1% perhaps.
When you buy a tracker, you are buying the index; in other words, you are deciding that you cannot beat the market!
The main differences will be with the quality of the administration and the charges applied to your investment.
Remember that the market can go down as well as up - and a tracker will follow the index down just as accurately!