I've had some of my pens since the '80s. Not all are fountain pens but that's irrelevant for this first comment. Some resin pens, such as the basic Montblanc, can crack if dropped. The lower body of two Montblanc rollerball pens I've had cracked. One not too bad so I still use it as-is, but the other was unusable with the crack. But the same happened to a Parker resin fountain pen. However, these pens were decades old before they cracked so perhaps years of constant use caused stress to the resin, weakening them.
Second, I don't use my fountain pens that often so the ink seems to just disappear over time. I assume the fluid evaporates but it doesn't even seem to leave any residue, which I find strange. So, if you don't plan on using them often, fountain pens my be a bit inconvenient, although no one uses a fountain pen for its convenience. I just checked and all my fountain pens are now empty even though they were filled a few months ago (probably longer ago than I think).
In general, I find my Montblancs comfortable to use with a nice feel when writing. But I would say the same for my other fountain pens so I'm not so sure anything I just said is very helpful. LOL
I guess the only real comment I can make is, I like my Montblancs.