I suppose Air Portugal (TAP) would be fine if you are traveling alone, and don't care where on the plane you sit. However, as a couple, we will never fly TAP again. They charged us $170 each ($340 total) for "Comfort Class" seating, but ultimately placed us in Economy, with no refund allowed for the $340 we paid. (I think that's called "theft.")
Comfort Class supposedly allowed us to have more legroom and, more importantly, choose assigned seating before the flight. However, at check-in for our outbound flight from Chicago TO Lisbon, they had placed us in different seats "Comfort Class" seats than we had chosen. The seats were admittedly together, but in the center of the plane, not by the window as we had paid for. When they offered to move us to window seats, we didn't realize those seats would be uncomfortable ones back in the "Economy" section. I guess we could reluctantly lived with that, even though it's a 9-hour flight.
However, on the return flight to Chicago, we did "on-line check-in" 20 hours before the flight, and they had put me in Row 9 and my wife in Row 32. I then called Customer Service, which (to their credit) does connect you with a representative fairly quickly. I calmly explained my situation to Rafael and after he understood the situation, he "put me on hold," but then hung up on me. I called back and talked to Jonathon, and he did the same thing. When I called back again and talked to Joanna, I told her I'd been "disconnected" twice, so she at least took my cell phone number, and explained that Comfort Seats had been "overbooked." She said our only two options were to go to the gate the next day and hope they could reassign our seats, OR she could put us (together) in Economy by the window but there would be NO OPPORTUNITY for a refund. When I tried to ask more questions, she claimed that my cell phone was "breaking up" (after 20 minutes of it being fine), and when I said to my wife that I wasn't going to hang up on Joanna (because the "signal might come back"), Joanna obviously could hear that just fine, and she hung up on me (and never called me back). Ultimately, we were able to use their App to choose Window seats IN ECONOMY for the return trip, but when I called TAP after the flight to inquire about a refund, they said no refund is allowed.
Overall, I supposed TAP would be OK as long as you only want (and only pay for) uncomfortable Economy Class seats, since that's what you are likely to get anyway.