Personally, I have always found Parkers to be too large (and heavy) for my hand, but they are exceptionally well constructed pens and well deserve their popularity.
As a teenager, and, at university, I tended to use Cross, Papermate, or Shaeffer pens, and, then discovered Caran d'Ache.
However, for more than the past decade, I have used Mont Blanc pens and love them, as, when writing with them, they glide easily across the page, and they feel as though they are an extension of my wrist.
Unfortunately Parker seems to have gone the way of "metal=good" on a lot of their models. The vintage Duofolds, Vacumatics, and 51s were quality, well balanced premium plastic(or hard rubber in the case of the early Duofold).
Without weighing but otherwise doing a big of in-hand comparison, the Duofold I show above is essentially the same size as a Pelikan M800 and would be the same size as a 146 if not for the cap finials on the latter. It's a tiny bit heavier than the 146, and a bit lighter than the M800. I'll add the caveat that the 146 to which I'm comparing doesn't have the brass piston threads-if I had one handy I'd compare the two(the Duofold is similar in weight to my newest 149, which does have a brass piston).
With that said, these pens are balanced differently. A lot of the weight in the M800 comes from the piston mechanism, which puts it way up high. I don't generally use my pens(especially the larger ones) posted so having a lot of weight high up feels unnatural to me. The Duofold has a lot of brass in the section and almost none up top, so is very bottom heavy. The 146 is more evenly balanced along its entire length. I prefer the balance of the 146 overall, but like the "low" weight of the Duofold over the "high" weight of the M800.
As for nibs-I almost find modern MBs too smooth. Many older ones have an almost perfect amount of feedback-they're like writing with a sharp #2 pencil. I tend to get new MBs in B or larger or in oblique grinds where possible as I find that these have better feedback than the glassy smooth F and Ms. Among other things, Pelikans are largely too smooth for my liking.