The thing I like best about the little one π and two π speakers is their simplicity. The Theater fours are in a different league, but the little one and two π speakers have a charm of their own.I have several speakers and while I spend a lot of time listening to the larger models, I probably spend more time in front of my two π speakers. The larger four π speakers can reach very high power levels effortlessly, and can deliver about 10dB more headroom at full power. But the one π and two π speakers sound very good too.
The difference between the one π and two π speakers is primarily found below 100Hz. There is quite a bit more bass available from the two π speakers. The trade-off is that they are larger, and I think the midrange of the smaller speakers might be a little more pure. Might be just the lack of deep bass though, making it seem this way.