Family Tree DNA are my company of choice for autosomal DNA testing. They are the only one of the big three DNA testing companies to sell their tests worldwide and, more importantly for those of us in the UK, they probably have the highest concentration of autosomal DNA test results from the British Isles, thus maximising your chances of finding a meaningful match. AncestryDNA don't even sell their autosomal product outside the US. 23andMe sell their test in 56 countries, including the UK, but they charge a hefty fee to despatch the kits by courier, which effectively doubles the price of the test. The majority of 23andMe customers have tested for health reasons and are less interested in genealogical research, whereas Family Tree DNA is a dedicated genetic genealogy company. For a comparison of the different autosomal tests see Tim Janzen's autosomal DNA testing comparison chart in the ISOGG Wiki. If you've not already taken the Family Finder test now is your big chance to do so. If you've already tested, you might like to encourage your friends and family to test as well. The Family Finder test works best when you have results from multiple family members, and the more people who participate the more success we will have.
The Big Y test is also included in the FTDNA sale. The Big Y test is an advanced test for people who wish to be involved in the Y-SNP discovery process, and is only available for existing FTDNA customers. See my previous blog post The new Big Y test from Family Tree DNA for further information about this test. If you are interested in taking the Big Y test you should consult with the administrators of your haplogroup project. If you're not already in a project you can find a list of Y-DNA haplogroup projects in the ISOGG Wiki. A new SNP matching feature is to be launched for the Big Y test in the next few weeks which should help with the SNP discovery process. For a comparison of the various Y-SNP tests see the Y-DNA SNP testing comparison chart in the Wiki.
Here is the e-mail that was sent out to Family Tree DNA group administrators. (Note that the dates are in US order with the month followed by the day.)