That's an interval, but it's not Tabata protocol.
There was some follow-up where the original researcher (Dr. Tabata) tested other interval protocols for their training effect.
First: note that as with any training protocol, "best" automatically implies "for what", and in the case of Tabata, the goal is increasing VO2 (maximum aerobic potential) in the trainee.
Varying the interval timing / workfactors from the 20/10 to other values reduces the VO2 max increase. The mechanism seems to be lactate production / oxygen debt, followed by a very brief recovery period. You can do other interval periods, and they may have their own training benefits, but if you're looking for a VO2 max benfit, toss in a 1-2x weekly Tabata set.
The whole matter of interval length and workfactor ratios (work to recovery) is something I've tried to research from time to time but there's surprisingly little written on the subject at least in lay accessible sources. The research on the strength training side (sets, reps, rest, training protocols) is much more accessible and advanced, from what I can tell. Hrm.... Wikipedia's actually got a good summary and compendium of references: http://en.wikipedia.org/wiki/High-intensity_interval_training