I looked into the same in 2017 for a 2018 trip, ended up landing on Portillo mainly for the ease of getting there with 8 people in our group. We only had a week, so the amount of time and cost for flights made flying Boston to Santiago much more appealing. Bariloche does look amazing, and there’s a good chance I’ll end up there one of these summers.
As for general info on Portillo, I’ve copied from a recent comment I made on SkiTalk, on a thread where someone was asking about Portillo vs. New Zealand:
I spent a week in Portillo in 2018. Had an amazing time. It’s like summer camp… everyone arrives together and leaves together (Saturday to Saturday stays). They don’t sell day tickets (unless the hotel isn’t sold out), so it’s never crowded. You meet people in the hotel, the bar or the discotheque, and become friends for the week. Everyone has a similar mindset sharing the same passion for skiing…I mean, why else would you spend your summer vacation in the Andes.
If a wide variety of groomer terrain is what you’re looking for, it’s probably not a first choice. But it has some world class lines if you’re a bit adventurous and are fortunate enough to get some good conditions. The incredible views, the history of the resort and the legend of the Laguna Del Inca are worth the visit alone. Oh, and slingshot lifts are something ever skier should experience at least once in their lifetime.
It’s a unique experience that I would recommend to anyone with a passion for skiing.
Here’s my trip report if you’re interested in diving in further. I’m happy to provide an details on planning or the experience if you have any questions:
https://www.skitalk.com/threads/trip-report-for-portillo-august-2018.11385/
Side note: I thought I posted a similar trip report here, but can’t seem to locate it.