I tested RBass with kick tracks, too, based on suggestions above.
Be careful when testing that you level-match and at least test with eyes closed if you can't do a true blind A/B. I found that I had to lower an RBass-treated kick between 6 and 10 decibels to get the same volume (determined both by ear and by RMS meters) as the unprocessed track. It's easy to fall into the trap of thinking something's been improved when in reality it's only been made louder.
RBass did indeed add some fullness when the frequency was set to around 60Hz. However, Voxengo LF Max Punch did that, too - but without killing the attack transients like RBass does.
My favorite method for beefing up kicks with low-frequency whump, though, is still layering a synth. This lets me precisely control how much whump, what frequency the whump centers on, how many harmonics to add to the whump, and the precise envelope of the whump. Assuming, of course, that a kick
needs more whump.