I really am not a fan of the Spot. I feel it is a poor substitute for a PLB. But here in the UK the Spot is one of the only options available to outdoor enthusiasts.
In the UK PLBs are not licenced for land use and you can not register them for such use.
This hopefully will change in the near future as there has been a number of petitions submitted to the government asking for PLBs to be licenced for land use.
On the 29th September 2008 the government announced to a reply to one of these partitions that 'the UK Search and Rescue Strategic Committee is set to consider the use of PLBs.'
http://www.number10.gov.uk/Page17001The only problem that remains is that many of the S&R teams in the UK are opposed to PLBs. This is in part to do with a misunderstanding of the technology. As well as data of misuse and accidental activation taken from the early days when EPIRBs were introduced.