Flying Lisbon to the Azores - airline comparison

I’ve flown TAP many times and Ryanair a few. I much prefer TAP, but can manage Ryanair, much as you wrote. When I stopped flying Ryanair is when they started charging for carryons larger than a laptop bag. No rolling carryons without a charge. If the price is still cheaper, I would likely go with Ryanair. But, since their change in baggage policy, TAP seems to be comparable if I add the baggage fee with Ryanair.

My normal airline to/from/throughout the islands is Azores Airlines/SATA. I have only flown TAP a few times to/from the Azores. I have never flown on Ryanair. I do have family in the Azores who have flown on Ryanair and they do not have any complaints.

The biggest issue you could encounter is due to weather. This is no one's fault. The second issue would be to mechanical problems. Azores Airlines/SATA is notorious for this. Their fleet is quite small, so if one of their Airbus planes cannot fly, they probably will try to quickly rent a plane from another company. If no planes are available, the domino effect takes place with concurrent cancellations. Who knows when you will be rebooked?

TAP has a much, much larger fleet and less instances of mechanical issues. They would not need to go looking to rent a plane on short notice. The odds are quite high on TAP that you will be rebooked on a new flight departing within a few hours to the same day.

As these are airlines operating under EU laws and regulations, they must offer compensation in the form of hotels, food, and taxi vouchers (been there/done that for both TAP and SATA) depending on how long you will be inconvenienced.