An Extension tube VS A dedicated Macro lens adapter?

After spending, and exploring, an year with my Canon 100mm f/2.8 Non IS Macro lens, I sometimes feel hungry to get even closer and to record even more details in the subject. Lately I have started getting back to the Reverse lens technique, but it surely is not the whole and sole option for higher magnification macro shots. I have seen few of my friends and photography lovers' works, who are into macro photography, use extensions tubes or Raynox DCR or both, to get really close, full frame shots, of the tiny beauties of nature. I am curious to know which one of these are a better option, an extension tube set or a Macro lens adapter like Raynox DCR 250.

In general one advantage that I see with Raynox is whenever I want to get closer to the subject I can just pop the adapter in front of my lens, rather than removing my lens and then fitting the extension tube and later fitting the macro lens.

I havent used neither the extension tube nor the Raynox, so was curious to know about them from our forum members and experts. DO let me know which would be a better option, this will help me in making the right decision, equipment wise as well as budget-wise.

Extension tubes work by simply adding a bit of distance between the rearmost lens element and the camera sensor. So extension tubes are not really 'optical'- they just add empty space, which allows you to reduce the minimum focusing distance and get closer. The Raynox is generally used to add pseudo-macro capability to a non-macro lens, such as a standard lens or a kit lens. I have never seen it used on a 1:1 macro lens.

With extension tubes, the absence of any optical glass means there is no chance of any reduction in image quality. Basically, you can't go wrong with extension tubes. As long as the electronic contacts are working, any extension tubes will do the job well.
With the Raynox, there is bound to be at least some drop in image quality, because you're adding more glass to the setup. How much of a drop this is, I don't know, as I've never used one of these.

If you're looking for an accessory for the 100mm Macro, I'd choose the extension tubes.

Agree with Abhishek about extension tubes. I also use extension tubes. Unlike you guys, I can't crop as I am filming and even in still photography I rarely crop.

Extension tubes will help you in getting more than 1:1 magnification.

How much time it takes to insert the extension tube?

Macro photography and filming needs very careful and deliberate approach. It is not like roaming around in a Safari in a jeep for few hours and then returning back. Slow approach helps. Also, unlike you guys I use tripods 100% of the time (with the 100mm IS macro lens). So you can imagine how much slower my approach would be from you guys. At the end of the day, when you get one great macro shot, close, perfectly composed with right depth of field and light, it is worth more than running and firing 20 OK shots.

Will post in detail later when I can share screen grabs.