My favorite pen of a long lifetime (mine, not the pen's) is a Mont Blanc Noblesse from the 1980s, a red one with a 14K fine nib, which I found in a charity shop in Melbourne about ten years ago for $5. The volunteer who sold it to me said she thought it was a cheapie from China. Good on her! It's a classic and worth a fair bit, but more importantly it's the best writer I've owned - I have about 50 in my collection box, so this is most definitely an "informed" comment, at least for me.
For reasons obvious the Mont Blanc rarely leaves home. A few years ago I was using it on a train in Indonesia, when I had finished writing my travel notes I put it in my travel pack but it fell out to the floor. A very kind lady in the seat across from me pointed this out to me. I owe that lovely woman a great deal, the loss of this pen would have devastated me.
Now and then I make a valiant effort to use several of my other pens but the Mont Blanc is by far my favorite. Currently on my desk as I write this is a fairly new Parker something or other (the box bears no information as to its "lineage" and I've not been able to trace it on any of the several pen web sites I occasionally check) I picked up in a charity shop in Springwood, New South Wales, last year for $8. It was a retirement gift to a lady named Emma R and is inscribed with her name, which obviously reduces its value to a collector but not to a user/writer.
My second favorite is a classic, a Parker 51 finished in rolled gold, dating to the 1960s, given to me as part of a set (pen and pencil) by a close friend (sadly long deceased) in Sydney in 1980. I've used it a few times but it occupies a place of honor in my collection box as whenever I take it out it triggers many happy memories of our friendship. I rarely use this pen, at most once a year, but it's a good writer.
the '00s saw a revival in FP usage. Many of my friends use them. They have mostly Parkers, Shaeffers or Kawecos and say the Liliputs are fine pens but fiddly to write with. I own three in their classic metal tins with all the accessories, but I have to say I've not really taken to them. Too small for my hand, maybe.
I have a few very old pens including two unusual Art Deco ones I picked up in Europe in the 1980s. At that time ('80s and '90s) fountain pens were being dumped by the zillions in favor of the newer fine-liners which everyone seemed to want to use, even we did in my architectural office in the '90s as they were, as they say, "cheap and cheerful", never leaked, were very fine-lined and once emptied could be thrown away (in the recycling bin) and new ones bought for about $1 each. I'm now retired and I have no idea if these pens are still in popular use or not. I'm now more into environmental issues and I try to no longer use anything that gets thrown out after its use-by, not that I'm particularly successful at this but we do have to try and it gives me a great sense of satisfaction to take out a bottle of Lamy ink and fill up an empty fountain pen - which sort of takes me back to the 1950s when I was a grade school kid and had two highly valued pens, cheapies of their time (probably Sheaffers) which invariably leaked blue ink and stained my shirt pockets...
I never did take to biros when they first appeared in the shops in eastern Canada (this was about 1959) as I found them difficult to write with. For me a fountain pen is more easily held and I can easily draw good letters of fine lines with one. So for me, the die was cast - or the ink, as it were.