Can’t help you with the Platinum Uno/Duo’s - but, from the YouTube video - they’re pretty impressive - very clear, detailed, extended highs and solid bass.
Just a note on the Harbeth 30.1’s... compared to my other speakers.
They’re bass is pretty good, but can be a bit overwhelming (mid-bass bloat), and require careful placement out into the room, and an amp with enough current and damping factor to control it (clean it up) - basically solid state. I use an A21, or pair of JC-1’s, with them and they sound pretty good - much better defined bass, and a bit more balanced.
I’m not a big bass lover... but... an "articulate," clear, balanced... bass lover.
Also... if you want them to provide appropriate extension, clarity and detail resolution in the highs - you also need a lot of current, and... I added the Townshend Super-Tweeters... to obtain that type of sound with them.
I’m also using a Audio Research Ref 5SE tube preamp with them - which helps them produce extended, clear, detailed and spacious highs, rich / organic mids, and solid, textured bass with spacious, airy stage and imaging.
Now then... with all of that they can provide a very big (room filling), balanced, resolved, spacious, rich, musical sound. They’re mids are especially rich, warm and textured with a sound similar to the Quad ESL 57’s - which are the best.
They can sound very good, depending upon the rest of your system... but... generally, seem to sound better with great solid state amps (e.g. Hegel, etc.), or solid state / tube hybrids (e.g. McIntosh SA252, etc.) - there are a few video’s on YouTube, that make the 30.1’s sound - incredible, with the Hegel H300, or the McIntosh SA252. They were the reason I got the 30.1’s.
The Legacy’s don’t require all of that - they’re AMT tweeter provides better highs and they’re bass is better controlled. I should add that I also have, and am biased towards, the Legacy Aeris speakers, which very few speakers can equal, or better in all respects. In addtion to their superb drivers, they are partially open baffle speakers, which provides an incredible stage and imaging - big sound - like dipole panel speakers. And... their clarity, detail, and resolution, approaches that of the ATC’s, or Proacs, or other studio monitors, without overly rich mids. The Legacy Clarus possesses much the same sound.
