FWIW, I bought the Datacolor one because of its price and the availability in Europe (for the LensAlign it has to pass from our custom, which is one of the slowest of the planet and add more or like 50% between duties and tax!)
The fixed 45° angle is way too steep. For the most of my lenses, even at full aperture, the DOF is so high that knowing what is really on focus is quite hard to tell.
Beside that, it's almost impossible to correctly align the focal plane of the DSLR as no help is given from the SpyderLensCal itself (while the LensAlign does help with that red circle alignment system).
So... I'm not even quite sure it helped my focusing or not. I mean... sometimes on the filed the focus is not achieved for low light conditions of just a few millimeters off the desired elements from the central focus point. It happens.
For those who can afford both the brands, go for the LensAlign, IMHO.