If price is the only deciding factor... You do realize you will have to buy bulbs to maintain the T5 fixture. The LED will not need such as most them last 50,000+ hours. Most likely unless these are brand new T5 bulbs you will have to buy 4 new bulbs at 20 each roughly. I usually change mine every 8 months and some people say every 6-9 months.
Now if quality is the most important factor..then the ATI T5 hands down is a great fixture. I still run a couple tanks with T5 and I like them a lot, but I have just bought a new LED for my new 40 breeder.
I think LED is the future and even a combo of T5 and LED maybe also in that future. I can't honestly speak on LED just yet as my tank isn't fully up and running.
One thing I have learned is if I know I'm going to buy a certain light that I know will be the final light. Then I will get that light even if it means it takes a month or two to get it.
Also the Mars Aqua is only $169.99 on Ebay
http://www.ebay.com/itm/390885496493...%3AMEBIDX%3AIT