I have been using a Groove pillow for several months now after injuring and then re-injuring my neck & shoulder sleeping with softer pillows before. It has completely changed my sleep quality. I never thought I would be able to sleep with 1 pillow, especially a flat, relatively thin one. I honestly think I would have had a recurrence of that injury without the Groove pillow.
My wife recently hurt her neck and after trying my pillow she also purchased one, and the difference for her has also been huge.
The service has been fantastic throughout, quick delivery and in my opinion a great price, especially as you can pay similar prices for a standard pillow that puts you in an awkward sleeping position.
Highly recommended.