This is why we should see measurements. We don't even know how much A300 outputs whilst being clean.
My own impression on desktop use is that PA5 has no problem defeating A300, but this could all be psychological, it's not easy to do A vs B quick enough or at the same output to really know.
The measurement does help, but i wonder, as mentioned many times in ASR, if our ears can detect the difference. What SINAD is good enough (80? 90? 100?)? If not, we are after or pay for something that are so food on paper, but give no practical benefits.
Listening is subjective as everyone knows. Most audiophiles like input direct, flat curves, but some people like a little Vshape ( in this threat, some one thinks the best setup for him is E1 with treble =2, bass=2).
I would like to see the measurement too, but it is not everything. I usually bought a device based on the reviews from some people here (e.g. Toku) or some reviews on internet that i follow, and give it a try in my modest system ( usually I buy from Amazon that has 30 day return policy if i dont like the product).
If you know what a good enough SINAD ( beyond that our ears can not detect) is, please let me know. Thanks.