I've quite a few hours in the C402 and C310 (R and Q variants). I preferred the 402 to the 310 but I preferred both of those to the PA31 and PA34s that I also used to fly
Not that I am in the market but currently there is no way that I would contemplate buying any of the 400 series. I would only consider a 310 IF it was such a steal that I could afford to walk away from it IF the spar AD permeates down to the 300 series.
Shame really but most 310s/4xx must be at least 30 odd yrs old!
Stik