I owned both: an ebay pair in the plastic packaging ($10) a real pair in the box ($35). The only major difference I can remember in terms of feel is the overall solidity of the real ones and also how the sliding headband is actually notched on the fakes and pretty much smooth on the originals. And also the sound - it's just more lively and present in the genuines ones. The fakes sound flat, veiled, and distant.
The headphone adjustment is the same on mine. On the genuine AT's it's notchy (as it should be) on the fake the adjustment is smooth. The Fake AT's SQ is full and deep compared to the real AT's which is ... thin to say the least, but good.
But there are differences. the thickness of the ear pads, the blue (ink looking) marks on the driver casing, and a few more. I hate to say it, but if the sound is .. bassy, then they're fake!