Generally, McIntosh and B&W work very well together. Mc has enough power and current to fully control what are relatively inefficient speakers like the 804. You might find the integrated amp doesn't reach the pinnacle of precision like separates can, but does nicely for most smaller listening environments. If possible, I'd suggest you give the system an audition and see if you might like one of the higher powered units better. The two brands are often sold in the same retailer, so shouldn't be too difficult to arrange.
Good luck & happy listening!
Good luck & happy listening!