I can tell you why almost all of our modular flooring products are at 1/2" from our point of view after manufacturing modular flooring for nearly 40 years.I'm sure every manufacturer ( or even resellers for that matter) will say why their product is better, there are tiles are 1/4" to over 1" ...
I will bulletize ( is that a word

) what we have learned to be best for our product use over the years.
* 1/2" allows for all doors opening inward to clear the flooring
* There is a fine balance with how much material you can use per square foot before you have expansion issues.For cosmetic reasons we do not want to use expansion joint inserts to remedy an issue
* We engineered the structural design for the garage over just adding more material to try and create strength
* Our product are U.S.A. made and engineered and all of our sizing meets US imperial sizes, not Metric . That is also why our products are 12" & 18" modules for best fit in garages
* Our patent locking system is the beefiest in the industry ( thick or thinner tiles) and also becomes part of the understructure. We engineered this specifically for the garage.
* all of our products interlock with one another, to create a truly custom floor for all your needs.
As I said, we believe we have the best American Made modular garage flooring in the industry based on our experience, history and customer feedback..Our competitors surely will disagree.... I would do a search ( here and on the web) and see what others say about their floor choices and then make the right choice for your own garage....
Here is link for a little more about RD Vs.
http://www.racedeck.com/whatisracedeckflooring.html
and a link to What Others have to say about RaceDeck
http://www.racedeck.com/testimonials.html