I ALWAYS thank clients for my reviews,i am always delighted to read what they have said and am extremly grateful for towards them for it.i dont do it publicly but i send them a pm to thank them and tell them how happy they made me.
although if a client texts me after the appointment and says thank you i rarely get back to them as i tend not to read texts and i dont like texting clients as i do worry i will text at an inappropriate time and get them in trouble!we cant have that!
But i totally agree with you ric, when someone goes to the trouble of writing a review and saying such kind words about you, the mannerly thing to do is to show your appreciation and thank them. I would nearly feel embarrassed if i didnt!