I'm presuming the surface detail on the Italeri Sunderland kits is similar to that on their Stirling kits. If that's the case, then the only very minor criticism I have, is that the engraving of the fuel tank covers on the wing upper surfaces is a touch heavy. But as previously mentioned, once painted, and with a gloss clear coat and matt clear coat, it should look fine, and I can live with that.
The internal detail (on the Stirling Mk1 kit) is very good indeed, with PE parts, including the internal frames on the gun turrets, and I believe the Sunderland kits have similar detail.
I discovered this after spending hours scratch-building internal detail on the Airfix kit, for a commission, when the kit was released part way through the work - needless to say, I bought the Italeri kit !!