Thermodynamic Solar Collector v Flat Plate Collector

Hi All, this is my first post on boards.ie. I was hoping someone could give me some advice on the above. I have had two solar installers give me quotations on both types of technology. I must also say that i have seen both there work and these guys do top quality work in my opinion.

The first was the Thermodynamic system. A 300l tank with one solar panel fully installed and commissioned = 5200 less a grant of 800. The second is a flat plate system including 2 x 2.5m2 solar panels, a 300l tank fully installed commissioned = 4900 less grant of 800.

As you can see there is only 300 in the price difference. My question is which system should i go for. My concerns on the thermodynamic system is it is relatively new technology and there isn't any hard evidence to be found on the internet regarding running costs. My concerns on the flat plate system is between say end of September to late March i will be burning oil on a larger tank than the 130 liter copper one i have now. Can anyone tell me which one is most cost effective to run.

All advice would be gratefully received.