While I wouldn't put them as my favorite, I do use Portugal fairly regularly and probably have them higher on my personal list than most players.
They're an odd civ to play, and their traits force me away from some certain wonders I otherwise try to snag as they will trigger a way too early GA, but I have had some BIZARRELY good luck with them. 2 AA SGLs while working my way up towards republic, for instance. Or back to back MGL spawns from the only two elite units (MDI's) I had at the time. Not an advantage you can count on having, of course, but positive associations like that will have you giving anyone further opportunities.
Alphabet + Fast Curraghs + Scouts means they always have a shot at early contacts and being the leading tech broker, though they kinda HAVE to be. And while the Carrack sounds great on paper (2.2.4[5 for seafaring] Caravel replacement, DOESN'T sink in ocean tiles) it really isn't as much an advantage as it sounds like it should be, due to the caravel's short time on the stage.
I wouldn't list them as a strong civ in terms of the classic 3 tiers, but they are a fun civ.