I have 2 ported 400s and 4 ported 462s. I know what they run like, I ran my first 462 until the piston finally cracked, it's a torch with a 20" bar and even a 24".
If you're gonna primarily run a 20" bar a 400 is a good buy, depending on what metric you use to determine what's "better"...if you're gonna cut hard dry wood with a 400 with an 84 driver chain you should upgrade the oil pump.
A 400 doesn't out cut a 462 with a 24" bar. I know some people that just play with chainsaws at the chainsaw games may tell you otherwise, it's not true. But it sounds like from your use a 400 is the ticket.