Boy, aren't you one to 'Wiff Woff' and prolong a decision.
Wiff Woff- bounce back and forth like a ping pong ball
Get the 20" Dewalt, wear it out and then buy a 33 1/3" saw or a 21"
Actually, the answer is to get the Dewalt and the Excalibur
Oh, you never said what saw you currently have.
Another thought is experience would tell you to get the bigger saw,
no experience would say, 'any saw will do.'