I think the consensus is that, as you go up a rung in size, the speakers deliver more scale, however the SE's deliver more detail (and, in my experience, far better imaging). If I had to choose between a 7200.2 and a 5200SE, I'm guessing I would go for the 5200SE, but your ears should decide.

Similarly, my gut feel is the 818v3 (as Meridian's reference) would be better than the 218 and I would try and pair that with the DSP speakers. While I haven't heard the 218, the 818v3 was a long way ahead of its predecessor.

Prolific music listener / Hi-Fi addict!