I used to love the fine detail my Arcam Alpha 8/8P amps used to dig up. If that combo has the Arcam Signature (It's all I ever owned of theirs) I'd call it warm and detailed with a great soundstage and imaging.
The Naim stuff I swapped it for has a lot less weighty sound but with more tuneful bass and is more evenly balanced across the low, mids and highs. The Naim is more refined perhaps but nowhere near as good as the Arcam with regards to fine details such as studio noise, finger-on-string noises, feint sounds back in the soundstage etc.