There are a few comments on Hornby and its DCC products in Phil Graingers regular DCC article in Model Rail this month.
Basically , he's got hold of 2 Select units . TCS decoders won't run on one - but will on the other (has someone managed to sort out the signal distortion on later production batches??)
He also indicates that Hornby were a bit unhappy about his previous review which stated that functions 5-8 were not working. Having put his "new toy" signal analyser on the Select , it seems the signal being sent for these functions by the Select is plain incorrect - hence they won't work
One retailer is advertising that they regard the warranty on any TCS decoder as null and void if it is run on a layout controlled by any Hornby DCC unit. This seems somewhat over the top - I've not seen any suggestion that TCS decoders are damaged in any way , simply that they can't recognise the signal with that level of distortion in it (see the "ring ring" thread)
However the Hornby decoder is another story , and the Model Rail article, while regretting the limited number of CV's supported, specifically praises the actual smoothness of running and performance at the rail. They do not make any suggestion that it is incompatible with other DCC systems - I'm not sure what system the reviewer normally uses , but as he is an established DCC user ,it won't have been the Select