What receiver would be an upgrade for new B&W 685s

My son is headed to college. I purchased him a set of B&W 685's for his graduation gift. Have them currently running on a Yamaha RX-V495.
I am looking to purchase him a decent integrated, or receiver as an upgrade to the Yamaha. I am leaning toward an integrated as this will be just for the b&w's. I have been looking at used NAD and rotel mostly but am open to anything. Seems like $300-$350 should buy a good used unit.
He listens to music off his itunes/mac laptop. I got him a good zu audio cable (headphone jack and RCA's) and a set of emotiva speaker wires. He listens to mostly newer electo/house music.
Will the step up to an older used Rotel/NAD be a big step up in sound quality? Consiering the HK 3490 at $260 new shipped. Advice?
Look at the Cambridge integrated they have a couple of amps in that price range. The NAD is also very good. I would look for something that has a good power supply and a solid 30 watts to 100watts.
I like Rotel and Nad, but second the Cambridge recommendation. I picked up a Cambridge 540a v2 a couple years ago for about $250. Sounds better than expected with total reliability.
I have spent hours here reading and researching, and am to the point where I am ready to buy.
Thesound and Blk you gave me exaclty what I needed. I will add the Cambridge to my list and do a bit of research on those. Is the Azur the newer line from what you have Blkadr?
Mine is the Azure 540a V2 -(a)for Azure. I have read that the v2 Azures (like mine) are better than the first version, but I have not compared them. Great value used amp. (IMO)
For that kind of "music" a Rotel or Music Hall int. is better,if he liked Bach a Cambrige would be.