I said they sound great all the way up to crossover. There is a little bump about 850 Hz, but the crossover actually brings down all that rising response better than you might expect from the look of the graph. Anyway, You can always cross lower since your compression drivers go down to 1K. Maybe it is the room, or the fact that they are set up in a system with crossover and another driver, but they sound and measure real good in my house. (warning! home measurements! I do not own a high quality meter, but I did calibrate my crappy meter using a good one) The deltas behave better in the real world than they do on paper in my opinion. I do not really know how loud they go at full power, but they are dance club loud with 125 watts pushing them.with that big sub I must admit I wonder why you want such a full range big box main speaker, but if you are contemplating running your mains without the sub sometimes, or you just want to have the option, the Delta would be a good choice. If you will always use the sub then you still have to think about the JBL route too (asuming a good recone job). Way smaller box and from what people say they are super clean and dynamic. I know, I am no help, but the choice is yours alone.
Thomas