If this is something you are going into yourself, ie not going through a 3rd party, it may be worth it I am not realy sure.
But if you are going through a 3rd party, ie a financial adviser etc., I doubt very much that it would be a good investment.
My parents went into one of these 15 odd years ago where you get 1/2 your money back come tax time and get a pay out in 20 years time, with the money from the thinnings to be used to manage the investment. In a nut shell the money from the thinnings was not enough to cover the costs and it went broke with my parents losing their money. I have also read previously that many of these investments are actually designed to go bankrupt and rob the investers of their money.
Even if this doesn't happen you are likely to be paying way over the price it costs to set up the investment (probably twice as much if not more) by the time the company and the promoter take thier cut.
Also look at the figures, take into account that they have probably made them look better than what they are and if Im right they are probably saying that you only pay $5k (after the tax rebate) for a return of $25k which means you make a profit of $20k over 20 years which isn't really that much when you think about it, you could definitely earn more in a managed share fund by the time you account for compound interest.
Just remember never go into an investment to save on tax and only take un-biased opinions.
If you were going into this investment on your own then just ignore the above dribble.
Cheers Pablo.