Hi Noel,
I fitted 34 analogue Cobalt point motors into a layout a year and a half ago. 16 failed, some were over driving at the end of their stroke but most needed a tap to get them to go again, but would stop working again after a few hours. DCC Concepts did replace them but denied there was an issue with them. They then confirmed by email earlier this year that they did have problems.
I also fitted 14 DCC ones to a layout which 2 failed.
The problem with a Digital Cobalt is the electronics are with the motor, if the motor fails you have to bin the whole thing.
For me this was enough and went in search of an alternative which I now use servos, cheaper and more reliable with a great controller from Loolee http://www.loolee.org
The DCC module can control up to 192 points!