Gosh, "super USB", well that must be the best...
There's no such thing as super USB.
The Ayre and the Arcam will accept both USB 1.1 and USB 2.0. USB 1.1, otherwise misleadingly known as "full speed" USB, will allow you to run up to 24/96 source material. Above that, it simply will not pass the bandwidth required.
So, to run higher sample rates (e.g., 24/176, 24/192), you need to use the newer USB 2.0 (which permits 40x the data as USB 1.1). The Ayre and the Arcam units support this (although your computer may not), but the Simaudio does not. In fact, the Simaudio states that its USB input will accept ONLY up to 16/48. If you want anything more than that, you need to convert the USB to some other digital format through an offboard converter, and then use that input into the Simaudio. Hence, while the Simaudio provides the capacity to run high def material, it will not accept it over USB....
Otherwise, if it matters, the flexibility of the Arcam and the Simaudio are greater than the Ayre. That is, they both have multiple digital inputs, accepting multiple formats. The Ayre has a single USB only it is a 100% dedicated, single-purpose USB DAC. Thus, if you want to run anything other than USB, or more than one digital source, the Ayre aint the one for you. Looks like none of them have volume control, if that matters. Also, from the literature, looks like the Simaudio will upsample internally. I know that the Ayre does not, and it looks like the Arcam doesn't either. The Arcam and the Ayre run asynchronous USB, while the Simaudio appears to address jitter through a "proprietary digital clocking system." Asynchronous USB is, by many, considered to be the best option these days. So, the feature set for each is different. The Arcam and the Ayre appear to offer state-of-the-art functionality over USB. The Simaudio does not. In fact, from the technical data, suggests that USB on the Simaudio may have been somewhat of an afterthought.
Sound-wise, that's up to you. Have an Ayre, and it sounds great. But no experience with the other two, so can't really say. There are also many, many other options in that general price range. I suspect that a search regarding USB DACs will give you more suggestions than you could possibly want.
There's no such thing as super USB.
The Ayre and the Arcam will accept both USB 1.1 and USB 2.0. USB 1.1, otherwise misleadingly known as "full speed" USB, will allow you to run up to 24/96 source material. Above that, it simply will not pass the bandwidth required.
So, to run higher sample rates (e.g., 24/176, 24/192), you need to use the newer USB 2.0 (which permits 40x the data as USB 1.1). The Ayre and the Arcam units support this (although your computer may not), but the Simaudio does not. In fact, the Simaudio states that its USB input will accept ONLY up to 16/48. If you want anything more than that, you need to convert the USB to some other digital format through an offboard converter, and then use that input into the Simaudio. Hence, while the Simaudio provides the capacity to run high def material, it will not accept it over USB....
Otherwise, if it matters, the flexibility of the Arcam and the Simaudio are greater than the Ayre. That is, they both have multiple digital inputs, accepting multiple formats. The Ayre has a single USB only it is a 100% dedicated, single-purpose USB DAC. Thus, if you want to run anything other than USB, or more than one digital source, the Ayre aint the one for you. Looks like none of them have volume control, if that matters. Also, from the literature, looks like the Simaudio will upsample internally. I know that the Ayre does not, and it looks like the Arcam doesn't either. The Arcam and the Ayre run asynchronous USB, while the Simaudio appears to address jitter through a "proprietary digital clocking system." Asynchronous USB is, by many, considered to be the best option these days. So, the feature set for each is different. The Arcam and the Ayre appear to offer state-of-the-art functionality over USB. The Simaudio does not. In fact, from the technical data, suggests that USB on the Simaudio may have been somewhat of an afterthought.
Sound-wise, that's up to you. Have an Ayre, and it sounds great. But no experience with the other two, so can't really say. There are also many, many other options in that general price range. I suspect that a search regarding USB DACs will give you more suggestions than you could possibly want.