The most comprehensive and detailed review appeared in the Short Wave Magazine.
Their product reviewer, John Wilson, is the world's leading authority on shortwave receivers. Here are the highlights of his findings:
On spurious signal rejection: "As far as I can remember I have never found any receiver, analogue or digital, which had such cleanliness, and the WR-G303i has set a new standard for others to emulate."
On S-meter: "... amongst the best I've seen outside of professional measuring receivers."
On sensitivity: "... higher than necessary in a receiver of its type..."
On variable IF bandwidth: "... a very useful feature and allows you to exactly match the filter bandwidth to the incoming signal ... once experienced never to be forgotten."
On documentation: "... clear and easy to understand, and has a detailed appendix on the use and setting up of the Professional Demodulator so that the user can investigate various software configurations - this is almost a hobby in itself."
The verdict: "If I had to choose between a Collins 95S-1 and the WR-G303i (ignoring the obvious fact that the 95S-1 tunes to 2 GHz), I would take the WR-G303i."