I despise the plastic handles on any saw myself. IMHO they vibrate more.
Compared my metal handle 501 with thick rubber coating to plastic handle one like on 4910 490.
Another guy with 590 620 noticed same thing and swapped handles on saws to see. He said metal handle on 590 also vibrated less then the cheap plastic handle. 620 with the plastic handle then vibrated more to him, testing.
Echo 4910 with the vibrating plastic handles. Here is what Corey did to go 572 metal full wrap on his tester back in the day. He stated as soon as went metal with rubber coating vibrations were lot less.
I have noticed the difference in my 501 with aluminum handle and thick rubber coating compared to my plastic handle one.
Not that I need a FW on 50cc but 50 buck for 501 half wrap new.
Buy a whole dang 572 kit for the price on a 501 handle too.
Clutch cover, handle, west coast spikes etc etc. Crazy good price