Interesting viewpoint. I've always trained in a gi, and looked at where it's unrealistic (in the South, lots of t-shirts, so can't depend upon using the fabric for leverage, etc.), but there is the other side. You do have to be aware of how your own clothing could be used against you (and a gi is pretty near "worst case" for this, so a good training tool), and any kind of jacket or heavy shirt starts to give you many of the benefits of a gi, as far as leverage and firm purchase.Depends on what kind of wrestling. But either would be great, although I'm a fan of working with a gi. I think it's more realistic, as people don't generally walk around in a rash guard or a singlet.