I can't speak for Arcam except that the make some very nice equipment from what I've seen in store and heard from others.
I can comment on Parasound however. I recently bought a Parasound Halo A21 amp and I am very impressed with the build quality, features and sound of this amp. I have had it for 2 weeks and can return it, but its a keeper. Very dynamic and musical. Its neutral sounding.
The Halo line seems better built than the Classic line. This amp weighs 60lbs and I dont think any thing in the Classic line comes close.
I hope this helps some!
Regards,
Larry