I compared the Opus to the Waida Stock 861 and the Wadia was my favorite. The Opus is very dynamic and sounds really good but the Wadia was better. The Opus also need a better power cord to compare. That being said, I think the Cap MKII is slightly above the $3500 limit. The suggestion for the modified 850 sounds like a reall good option as does the Bon Mod Sony.
Happy Listening.
Happy Listening.