I've used the Scrubbing Bubbles Automatic Shower Cleaner in my master bath shower for just over three months and have been very dissappointed. I used it just as directed: Run once daily after the last shower of the day. I found that one bottle lasts about four weeks, as do the batteries. The device is powered by 4 AA batteries. I used a high quality battery each time, and found that they only last about 4 weeks, and then need to be replaced. When factoring in the cost of batteries to operate the device, it is expensive.
Besides being expensive, I didn't find the device to be effective at all. It did not improve the cleaness of my shower, or maintain it after I manually cleaned it. In particular, hard to reach areas, such as under wall-mounted soap holder, corners, edges, and the shower door ledge, were not reach by the cleaner dispenser, and collected significant build up. The glass shower door also had significant build up. In fact with just use by my husband and myself, my shower collected significant build-up in many areas, and I wonder would it have been the same had I not used this product at all. It performed that poorly.
I have used various brands of daily trigger spray shower cleaners for years, and now will continue to do so. With a spray bottle, I can better reach hard to reach areas, and focus more cleaning product in the areas which have more build up potential. These manual type cleaners have demonstrated themselves to be much more effective than the automatic shower cleaner, as well as much less expensive.