I have never heard the 3252N, but I would be worried about the crossover. Isn't it pretty high for a 15 inch driver? As others have said, it would be very interesting to listen to them side by side with the other JBL Cinema models.
This weekend, I actually heard a demo with three 3677's in front. To be honest, I think they sounded a little harsh. This was a setup with no correction and the room had some flutter echo, so this is probably some of the blame. But there is not doubt that the 3677's are not as smooth sounding as the HF on the 4722. But the 3677 definately has much of the qualities I like about JBL Pro cinema speakers and I think my audiotion could be improved with some (manual) correction and more room treatments.
Home Theater: JBL M2 & SUB18 powered by Crown and BSS.