I managed to have a go with both the Osmo and Karma Grip at work. It may sound silly, but the Karma feels like it’s ‘built like a GoPro’ i.e. reasonably robust, whereas the Osmo had all the little vents, fans and things. Karma quieter too. <span style=”font-size: 12.8px;”>The ability to reposition the camera on the Karma by grabbing it rather than fiddling with the Osmo Joystick was nice too, in fact, the whole thing seems more glove/cold hands friendly.</span>
Haven’t tried the extension.
As far as stabilisation goes they both do the job (as far as I pushed them, anyway) but the Osmo seems to have a stronger lock vs the Karma following your movements more ‘naturally’. Subjective, I know, but that’s about all I can offer.