I knew the Brahms, so that was always going to be OK... I was now relying on the musicians and the recording engineer if this was going to be the CD I hoped for. Oh! what a find! Gastinel and Guy are sublime and the recording is absolutely flawless.
If you're unfamiliar with the Sonatas, don't worry, just pick a vendor and send for it. The second is particularly fine... the mature Brahms, written around the time of his 4th symphony.