The answer is a a wholehearted "mostly". The heart of the question is why the Sensor Gel Stick does well for a large scale manufacturing/servicing organization, and a lot of that has to do with its easy of usage. Of course, it wouldn't be used if it didn't work, and to that end, it does. The method of action is straightforward:
- Follow the instructions for preparing your camera for sensor cleaning. For DSLR's, this invariably means starting with a fully charged battery and working in a clean, well-lit room.
- As always, start off with a dust blower to knock off the loose dust first.
- Press the gel head straight down into the the portion of the sensor where the dust is. Do not swirl or rub. Do not use force (obviously) but do press deliberately so that there is adequate contact.
- Lift straight up. The gel has a stronger adhesion to dust than the dust does to the glass.
- Press the gel head into the supplied special adhesive paper. The paper has a stronger attraction to dust than the dust as to the gel. If you were successful you should see dust spots on the adhesive paper.
Used carefully, the expected lifetime of the gel stick is a couple of years. The manufacturer says that the gel is also able to lift fresh oil spots off of the glass, but not aged ones where the oil has become hard through oxidation. Unlike a reusable lint-roller brush, the gel head does not need any additional cleaning after use; the adhesive paper should remove all of the debris from the gel.
Does it Work?
Yes, very well in fact. However it is not foolproof. Very stubborn dust spots and aged oil droplets can require multiple passes or not be successful at all.In such situations, you will still need to resort to a wet cleaning method. This comes back to the reason why the Sensor Gel Stick is amenable to manufacturing facilities and service depots; it's fast and it's easy. Wet cleaning is tedious and time consuming when you have a high volume of cameras to work through. The product is not cheap ($48.99 USD) but amortized over the expected lifespan it is more cost effective per cleaning than wet kits.
Addendum: Warning for Sony Mirrorless Users
The original (blue)_Sensor Gel Stick is not compatible with the coatings used on the sensor of some Sony Cameras. From Sony:
"Sony’s proprietary coating technology on its mirrorless cameras might cause the Sensor Gel Stick to leave some residue on the surface of the sensor filter, which will require thorough wet cleaning. The residue can be removed with a wet cleaning solution, but might take significant effort to clean it. Therefore, we recommend that you do NOT use the Sensor Gel Stick on Sony mirrorless cameras listed below. The manufacturer of the Sensor Gel Stick is working on a different solution to clean Sony sensors, so we are planning to start offering a Sony-specific version of the Sensor Gel Stick soon. Here is the list of Sony camera models that are affected: Sony A7R, Sony A7, Sony A5000, Sony A6000, Sony NEX-7, Sony NEX-6, Sony NEX-5 (all models), Sony NEX-3 (all models). We have not heard of any other reports regarding other brand cameras."
There is a Sony specific version available that is safe for these cameras. Fittingly, the gel is an orange colour for easy differentiation.