I like riding Keystone, it's not my favorite mountain, but I enjoy going there. So what are you recommending to him? I say the epic local because it gives him 5 resorts, and if any gets a dump of pow they are all within driving distance.
I love Keystone. There are many reasons to like Keystone. Keystone has great trees. Keystone has snow cat tours. Keystone has good hikes. Keystone has long trails. Keystone has good lifts. Breckenridge's lifts are a cluster fuck. Keystone has a gondola that serves ridable terrain. Breckenridge's lame ass gondola does not It's purpose is to increase the value of Vail properties (lame). This is an important factor if it is butt ass cold during your trip. Breck is cold.
Breckenridge gets more snow, but it blows off the mountain. Trust me on this, they call it Breckenwind and Breckefridge. Always bring a face mask to Breck.
Breckenridge has way longer, flatter and more prevalent cat walks than keystone.
I have had more issues with ski patrol at Breckenridge than Keystone. I spend way less time there. Breckenridge has a lot of no jumping signs and they put them on all the good rollers. Breckenridge put a no jumping sign on this awesome roller on peak 9. It was one of the redeeming qualities of the mountain. I almost lost my pass because of that stupid roller. I can't resist that roller. There is only one no jumping sign at keystone and that fucker is hard to resist too.
The smaller mountains don't give a shit about the rollers and leave them alone. It's nice not to have to look over my shoulder.
Peak 8 is so busy. There are more mega condos at the base of Breckenridge, this means more gapers. Breckenridge has the highest concentration of bro brahs. Some of the Breckenridge locals are very arrogant. This is true for many mountains.
Breckenridge aint my favorite mountain.
Of course everyone is going to have their opinions on mountains based on their own experiences. I know both Breck and Keystone pretty good. I have lived in Summit for most of my 20's. I aint in the 20s anymore.