Unless bad ...

The transmission of lens data, and the use of the picture stabilizer and the AF function well. The latter is dependent on light and object as well as the coupling of several rings at once. Autofocus has particular by problems that in particular in combination (total 65mm) is extremely lost a lot of light.

The rings are processed sufficiently robust. The first impression, however, makes them look inferior due to the weight. A safe for doing more serious deficiency is the fact that the rings, some rotational play have because the stopper screws not sit right. That is also the reason for the star trigger. It concerns in particular the 31mm ring. The other two, the game is considerably lower, but it potentiates naturally when used in combination of several rings.

However, I have made myself in this respect not much worry. The rings snap well and keep the contacts sit despite the game another neat. The heaviest look I had on hand was the Tamron 24-70 VC with 825g.
If the lenses are heavier and screwing the tripod to the clip instead of the camera one has the maximum weight to be held anyway capped by the camera.
With the 5D III, it was still okay. With the BG I have not tested it. 1D users will want to maybe grab more to the originals in order to have peace of mind where I can scare since the pricing policy. 170, - to transfer MSRP for a 25er intermediate ring which does nothing more than the objective data?!?!? For two intermediate rings you get a used 100mm macro 2.8er without significant light loss. Well, to each his own ...

I think the 40mm pancake as "macro" lens for intermediate rings as well, since it is extremely light and sharply defined even at full aperture. Disadvantage may be possibly the bokeh here. However, everyone must decide for themselves. I use the combi like.

Overall, I recommend the rings as well on (the super's missing then but unfortunately). Aside from the game at the 31er is all right. Maybe I have since also a Monday model.

Delivered the rings twisted together incl. Cover for front and rear in a small black cloth bag with velvet coating and a conversion table with the factors to lower the rings the light transmission. Very commendable. Price / performance ratio in any case.