I've had my Shen-Hao for a couple of years (the HZX45-II) and it's performed very well. Compared to the Tachihara, it has a Graflok back, more movements, slightly longer bellows extension, interchangeable bellows, and weighs more. The Tachihara is lighter, has a spring back, and handles short lenses more easily with the standard bellows, but the bellows are fixed so you can't replace them. The Tachihara has all of the movements most people would need for landscape work, but for architectural work the Shen-Hao is likelier to be the better match.
After two years of heavy use, my camera still looks and performs like new. The biggest gripe that I've had with the camera is that the knobs that control the rise/fall and lock on the front standard are small and not the easiest to work with (especially if you lock them down very tightly; a bad habit that I've not yet broken). I solved this by picking up a couple of model car tires at a hobby shop and stretching them over the knobs. A couple of dollars to fix the greatest shortcoming the camera had for me is reasonable, given the low price of the camera and the way it's held up.
The Shen-Hao is heavier than the Tachihara; if this matters to you then you might want to find out if you can live with the spring back on the Tachihara. There are solutions made for spring backs for many of the things that a Graflok back is normally used for (for example, Calumet had a roll film holder that would slide under a spring back).
There have been some reports of QC issues with the Shen-Hao camera on the web, but there are also plenty of people who are happy with the camera (myself included). I don't think that the QC process at Shen-Hao can come close to the work that's done at a company like Ebony (one of the reasons that the Shen-Hao can be sold for so much less), but I also believe that if all of the cameras coming out of Shen-Hao were dogs then the companies distributing them would have dropped them a long time ago. If you have concerns about the quality of a particular camera, try calling up Midwest Photo Exchange and/or Badger Graphic to see if they'd be willing to inspect a camera for you before they send it out. Since both of these companies are going to stand behind the product that they sell to you, I'd imagine they'd be willing to work with you before the sale in order to avoid any headaches later on. I have no experience actually doing this, but common sense tells me that these people want you to be happy so they don't have to spend a lot of time supporting you after the sale...they make their money selling, not problem solving.
If you're buying new, buy from a reputable company (Midwest and Badger would be my two recommendations) and if you get a bad camera they'll help you out. If you're buying used, make sure you have some form of recourse if there's a problem. Between these two cameras, I made my decision based on the greater flexibility of the Shen-Hao. I didn't care about the additional weight. I bought my camera from Midwest, and have been happy with the purchase. Had there been a problem, I'm sure Jim at Midwest would have worked with me to solve the problem...he's got a good reputation among LF photographers.
Good luck with your decision.
