The logistics of using this product are a bit tricky because you need to leave it in for 3-5 minutes while showering. I usually take quick showers so I've had to adjust my routine a bit, especially to avoid rinsing out the product as it sits for 5 min. I used it on top of the deep conditioning treatment and friends definitely noticed that my color was more enhanced between washes. In my experience, the deep conditioning treatment was pretty quick to fade, so I'd definitely suggest this product for maintenance.
Also -- I initially tried to color my hair just using this because I was afraid of having too intense of a color change. On my dark blonde hair, that didn't work :P