Nobody can say with certainty whether this is a good time. Several other threads have discussed this. Of course it would be an valid comment to say that now is the best time to invest for the past 5 years or so, since most funds have fallen to 2003 levels. However of course they can fall further, but they have lost quite a lot of value already.
I can offer my perspective as I have just decideded not to take such a tracker.
I think it depends on how important it is to you that the money invested is available at the end of the term. If you were able to leave the money invested for several years after that point if you had to, then a standard fund would be more likely to give a better return. Or you could cash out early if there was a good gain in 3-4-5 years.
I assume your tracker averages the fund value over a period at the end? So I had the nightmare thought that the fund would just have it's worst period over the averaged period and I would have no option to wait even a few months to see if there was a bounce. Of course you will get back your initial investment.
So, if this is your only investment, then I might take a tracker. However if it's only part of your money then a standard fund might be better. The tracker though is certainly a safer bet.
Ix.