Not used a Sinar camera since the days of 5x4 and I was never very impressed with them then. Sure, they were capable of great shots but I never felt they were the most stable camera platform. Never a massive issue with film but problematic with todays digital backs.
My experience with Sinar tarnished my view of their cameras and never looked at the more modern ones like the X so they are probably excellent. However, hand on heart I will admit to being totally bias in my love for everything Arca Swiss. If you want a rock solid digital platform I would look no further thant the (Monolith) M-Line 2 MF or the full M-Line camera. Exquisite engineering, precision and built like a tank is not normally something you read in the same sentence however, this fully describes the wonderful Arca Swiss Monolith cameras.
Lenses are good from both Schneider and Rodenstock but my favourite product lens is the RS90 HR-W (I'm selling one in the sale section) or if you are feeling flush the newer version the HR-SW. Big image circle, very little fall off, not LCC needed usually and super sharp even up close.
I recently joined getdpi and also recently acquired a p65+ digital back. I use it with my rz67 for fashion portraits, and am looking to find a view camera setup for wristwatch photography. I hope you dont mind my asking but you seem to be very knowledable on the subject and would you point me in the right direction? People have suggested sinar X with a rodenstock lens but i am not sure of the specifics. thanks in advance all the best MIKE MELLIA