I've skied Portillo (planned w 3 friends via their website) as well as Valle Nevado and Chillan booked with the Atlanta Ski Club, and a second trip to VN booked via US travel agent. Also skied Argentina (Bariloche & Chapelco) w ATL Ski Club. Portillo & VN are within a couple of hours of Santiago (ski the day you fly in!), Chillan was a 5+ hour bus ride from there. Resorts in Argentina are a plane ride away from Buenos Aires.
Chile could be compared to a cruise ship where you can ski, there isn't a village per se, just a few types of accommodation and several restaurants, VN has a few shops. Portillo is limited in terms of amenities, one restaurant plus a snack bar or mountain top restaurant for lunch if you choose, but it's a stunning location. Most are all inclusive (lodging, meals, lift ticket) with your bar tab separate. Portillo's website is sophisticated enough to handle your booking, we booked VN via a US travel agent last summer because of a language barrier when I called to book direct, we wanted to be sure it was all set up properly...and we got a nice last-minute discount to boot!
I liked the skiing better in Chile, the terrain is more vast than Argentina. Argentina is lower altitude and is more susceptible to poor conditions, and they don't have on-mountain lodging where I went. You stay in a town and shuttle to the slopes daily (up to 30 minute drive) vs. skiing out the back door in Chile. My sentimental favorite is Valle Nevado because I met my husband on my first trip there. I would recommend going in August when conditions are more likely to be ideal. And keep your eyes peeled for teams training in the area for some ski celebrity sightings...being wakened everyday (Portillo) to the sounds of Bode Miller & Co. shusshing down their training runs, or having dinner "with" Shaun White (VN)!
I'm going with the Atlanta Ski Club to Bariloche this August, spots are still available if anyone is interested. Happy to provide more detail on individual resorts as needed, I know this was already a long post!