It's not a popular UK extension, I don't think I have ever seen an advertisement using one! I think a lot of UK web users may even still be suprised to know it even existed.
Maybe in a few years...The .org.uk is popular and well known, I would def reg and use these.
You could use a .me.uk for search engine optimisation if you had a good generic search term...Google does not recognise any difference between .co.uk, .org.uk or .me.uk