A couple of specific questions. Does anyone have experience taking Flixbus in Slovakia? I am looking at the route from Stary Smokovec to the Budapest airport. Also, any hints about the train from Bratislava to Poprad?
Not in Slovakia. I've used FLIX in Portugal and Italy and was very satisfied.
No experience but I was just looking at your options: Flixbus or shuttle to Budapest airport. I have not ridden Flixbus in Slovakia but rode it from Lviv to the border of Hungary (and the same bus was continuing on to Budapest) and it was very comfortable and inexpensive. So I would be balancing out price, timing of departure, AND whatever info you can find on how long at the border. I would wonder if shuttle and bus take on average the same amount of time.
For the train, also no experience - but I would be buying a ticket for the direct train (changes are a touch more trouble). Every train I have ever ridden, including the 10 hr train Montenegro to Belgrade, has been fine. Not all are equally luxurious - but I can do almost anything for 4 hours. So I wouldn’t hesitate myself.
I also just went down this rabbit hole. 🤣 It might be helpful.
https://youtu.be/PNI5yUL7kGQ?si=X8b5CgZU05BRDtwg
or this?
https://worldviewstream.com/location/slovakia/