No better than a memory foam cushion
I think the key words are "can help".  My office chair is hard, so this is better than nothing.  So far it has not relieved my back pains from sitting all day, but it is better.  The main gripe I have with the Purple cushion is that it keeps falling off my chair when I get up.  The cover does have rubber nubs on the bottom, presumably for grip.  It doesn't move around while sitting, but it can be easily brushed off your chair when you get up.  Perhaps it grabs better on leather or vinyl seats?  Overall I've been unimpressed with this cushion, especially for the price.  A memory foam cushion for about half the price works about as well.
Rating: 3 stars