bottled ink or cartridges?

Caution – this topic may be more controversial than last year’s election!  OK, now that I have your attention I have a simple question.  Do you use bottled ink or cartridges in your fountain pens?  One can make arguments for both sides.  On the one hand there are many, many choices of bottled ink.  Visit any pen store and you will be amazed at the choices of colors from a variety of manufacturers.  On the other hand if you travel, particularly by plane, it may not be so convenient to carry bottles of ink in your luggage.  In that case cartridges might be a better choice.  On a recent trip to Bromfield Pen Shop in Boston I was pleasantly surprised by the many choices of cartridges.  I realize most vintage pens and some modern ones only fill from a bottle.  That being said, there are many pens available today that can go either way.  What do you prefer?  Please share your thoughts.
Happy Collecting!