Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Best $40 I ever spent

Caveat - I only use this as a massager. This is the only massager I have ever found that actually relaxes the deeper muscles in my back. This morning when I got up, my back was in full-on spasm; I could barely get out of bed. 5 minutes with my Hitachi, and I could move about like normal.