I use the metal 4x5. I like it for a small viewcamera. It is a bit of a puzzle to open and square up, but it is solid and easy to use. Make sure you can adapt your lensboards to the camera (if you already have pre-existing lensboards). For 5x7 I use a Deardorff, but if I were starting over would probably buy the wood Canham.
They don't seem to reply to email, at least my one try. I've heard that phone service is okay, but no personal experience.
I have the 4x5 model. I'm told that the only difference between the two is the size so I will give you my experience with the DLC. I have used it for about 8-9 months now, and think that it is a great camera. It is light, has lots of extension, and plenty of movements. Sometimes I wish it had geard movements but then I remember how light it is and that feeling goes away. I bought it used so I have never delt with the company but am told that they have top notch customer service.
I have had the metal 5x7 for about three years, and I think it is a fine camera. No, it does not have geared movements (except front and rear focus, of course), but in all other respects is a fantastic light camera. It is highly backpackable, and will accept the new 6x17 roll film back if you want to do some panoramic chromes. Keith Canham is an absolute pleasure to deal with. In fact, I just got off of the phone with him a few moments ago. He never overpromises on delivery times, and he will always fix any problems very quickly. He doesn't use email too much, mostly because he is busy building cameras, I suspect. I would recommend giving him a phone call if you have any questions, or contact one of his dealers such as Fred Newman or Dennis Kibbe at www.viewcamerastore.com who have a more active 'web presence'. I am sure Fred would be glad to send you a brochure if you emailed him.
I think Tuan's large format site did a detailed test of the camera. I used a Canham 5x7 wood camera for a couple of years before deciding that I'd be happier with a more precise, rigid monorail camera.
That said, Keith is great to talk to and seems to be an honest, straightforward guy. I'd recommend you give him a call.
Another dealer I can recommend is Ray Ng at Photo Habitat in NYC. He's been a Canham dealer since the beginning and is a very reputable guy himself.