I have one on the way myself. Brett over at Hyperscale has a few shots of his finished P-61. Looks like the biggest blunder is with the cowl openings but that's easy enough to fix with a little old fashion modeling... Or a little new fashion resin! :)
His comment was that it was a superbly fitting kit and required no filler even with it's complex shape. I have been begging for a new tooled 1/48 scale kit of the Black Widow for years and years and I can not wait to rip into it!