I found ratings of around 20k waterproofing and 625 breathability. Even though these tests can be extremely subjective, that breathability rating is no good (Gore-tex/Gelanots/eVent are all at least 20k).
HyVent, the jacket material, is a PU-based material and the Gonzo jacket has the 2L flavour. My understanding from the TNF site is that there is no DWR coating on the 2L. This means that water won't really 'bead up' and run off like the three fabrics I mentioned earlier.
I have not used or even seen this jacket in person so I cannot comment on how it is, but I would generally recommend a jacket with fully taped (or welded) seams, a DWR, and 3L construction (shells only, not the insulated variety). The Gonzo only appears to have taped seams. I do have an older TNF rain jacket with HyVent and its pretty much rubbish in most harder/longer rain storms. Hence, I would look elsewhere for a jacket.