I recently spent time in Lisbon and it's an ok city but I wasn't overly impressed vs. Southern Spain. Personally, I'd look at Southern Spain vs. Lisbon. Besides the obvious language barriers of learning Portuguese (I assume you already speak Spanish). I found Southern Spain to be VERY affordable. The beaches were fabulous and the cost of living was VERY good compared to Buenos Aires. I really enjoyed Marbella and there are a ton of cities along the coast where you can get a reasonable rent. Restaurants were VERY affordable compared to Buenos Aires.
The quality of life was really high. It's shocking how expensive Buenos Aires has become. There is very little tourism there compared to years ago. If you go to restaurants, they used to be full of tourists but now it's just mostly locals. I just came back from a trip there and the restaurants are more expensive than the USA now. I found the city to be cleaner, security looks to be better as I noticed much more police around several neighborhoods. But it's really super expensive now.
Spain would be a good call vs. Portugal, IMHO. I had a friend move to Nerja, Spain a few years ago and he loves it. He has kids and living a really high quality of life for not too much money.
