Hi Alfavela and All,
Decisions, decisions...
Sue you listed the major drawbacks of a "wheeled" suitcase, in addition to what has already been mentioned in this thread, the worst enemy is the cobblestones!
Alfavela, the question you need to ask yourself is can you carry the weight of a loaded backpack on your back? If you travel light, and I would advise that, you may find that you can easily handle a back pack.
Or, you might buy a combination backpack with wheels. These are real handy. I have one of these and I use it when I go to the University where I am a student. When I use the stairs I put it on as a backpack and when I am rushing from class to class I roll it, unlike you I'm no spring chicken, so rolling is wonderful.
In order to make your decision a good idea is to try each one out for a day and see which one you are most comfortable using.
For travelling I prefer the a small wheeled carryon, mainly because it's easy on my back and it gives me a lot of independence. Through the years I've learned to pack as light as I can.
If you feel comfortable in Miami(I've lived there) you will not have any problems in Spain. Use the same safety skills you use in Miami and you won't have any problems.
Buena Suerte y Buen Viaje!
________
Booklady: Who Totes Tons of Heavy Books Daily