I listened to a Raven Audio Osprey and Primaluna Dialog Premium HP a few months ago on the same day, same equipment. Truth be told they're more similar than different. Both have excellent dynamics as far as tube amps go, very clear sound, and you get the holographic three dimensional sound without being overly lush or warm. So from an SQ perspective, it's a wash. Now when it comes to looks, the Raven Audio looks much better to me, and yes I know its very subjective.
For me the choice was clear. If the price and sound quality are on par, why not spend your money to support a local business (Dave and James of Raven are fellow Texans). Because Raven bypasses the middleman, a better portion of the cost goes towards parts and craftsmanship. I eventually bought the Blackhawk MK3 and have enjoyed it very much in the 3 months that I've owned it. BTW, don't let the 20 watts output fool you. It plays as loud, but with more refinement and control, than my previous amp, the 100 watt Cronus Magnum II. Having said that, let's be real -- it's not a giant killer. It does very well within it's own price bracket but no, it's not going to better a tube amp costing $10k. I briefly had an Audio Research GSi75 in the house and compared it to the Blackhawk. Sorry, not even close! I ended up selling it for other reasons but still miss it to date.