I assume the HDH is the HTC Desire HD?
If so, I own all three of these phones and have some feedback for you. The Atrix has the best hardware of the lot (by a mile), but is let down by weak software (Motoblur) and capped upload speeds. The screen on the Atrix is quite good, but I find it a bit washed out. As for the dual-core processor, it is screaming fast, but there is very little software optimized to make use of the processor.
As for the Incredible S and Desire HD, both are quite similar and the main differences are the 4.3" screen on the HD compared to 4" on the IS as well as a front facing camera on the IS. In the real world, the lack of a dual core processor is not apparent today as these two felt as fast as the Atrix. I prefer the HTC Sense to the Motoblur (plus the fact that neither of these capped upload speeds like the Atrix), so overall my preference would be either of the two phones. I found the form factor of the 4" IS was more to my liking as I could use it one handed and hence I'll be sticking to the IS for some time (at least till the HTC dual cores come out). I really wanted to like the Atrix, but I just couldn't live with it's deficiencies.
BTW, both the Atrix and IS have locked bootloaders, so if you want to play with custom ROM's, the Desire HD would be your only choice.
Samsung Galaxy S III
Sony Xperia ZL - gone after 5 days!
Google Nexus 7
Samsung Galaxy S 4