I've been following the studio for almost a year now and I fell in love with them, so much so, that I wish I had some sort of talent or skills to have a career in game development because I would happily relocate and apply for a post at their company.
The biggest compliment i can give them is their treatment of staff. Every month they have various team building exercises, as well as awards for individual staff members hitting various milestones, such as time spent with the studio, achieving new qualifications and positions etc. Honestly it looks like a fun place to work, but at the same time, extremely professional. As the OP said, they were involved with The Witcher 3 and we all know of the success of that game, but they are also involved in a lot of other great pieces of work, as well as having a good relationship with Sega from their Mega Drive collections.
It's also interesting to note they are a Keywords company, who own Lakysha Digital, who are involved with the development of Shenmue 3. Any sort of cross development between the two certainly wouldn't be too difficult to achieve. But yea, I've had good vibes from them from when I first heard of them, and outside of the major players such as Bluepoint, I couldn't be happier Shenmue HD is in their hands.