I've owned the Airmotiv 4's for about a year now. They are definitely an incredible set of speakers. In terms of bass, placement is key as they are rear ported cabinets. At an optimum distance from the wall, these leave little to be desired in terms of bass (watching movies, listening to music, what have you). The sound on them is excellent and they are very crisp and clear. I auditioned a set of the Paradigm Shift (atom) powered monitors about two weeks ago and was very impressed, also. In my opinion, they blow the Airmotiv 4's out of the water. This is partly due to the larger driver size and built in DAC, but man oh man. If you have the money, I'd go for the Paradigms. They start at 279/ea and if you go for a gloss finish one it's going to be 329/ea. Entirely worth it if you're going to be spending a lot of time using them. Overall, though, you can't go wrong with either. If money is an issue, go for the Airmotiv 4's. If it's not, go with the Paradigms. I can't comment on the Airmotiv 5's but I can tell you that I'd be surprised if they held a candle to the Paradigms. Hope this helps.