We've stayed at a 1bd villa a BWL and also a regular room (pool/marina view) at Poly, so I can't compare the room size, but the feel of the resorts is very different. Poly always felt like a fun tropical party, but not in a bad way (you can avoid the party atmosphere and enjoy quiet walks on the paths). WL definitely feels woodsy/rustic and it's so well designed you can't believe you're still in Orlando FL. It's a really beautiful resort. The Lobby is simply stunning. Poly is nice but I wasn't blown away by the lobby or main building. The main pool at Poly is def crowded. We mostly did the DVC pool at WL but hopped over to the WL main pool and it didn't feel as crowded as Poly.
For dining I think they are pretty comparable, esp. now that Artists Pointe is reopened. Probably just a hard to get a res at Ohana as Artiste Point, and both are great (but no characters at Ohana for now). The quick service restaurant is very similar at both. There's a REALLY great outdoor bar at WL, and the Poly has a wonderful outdoor walk up bar with outdoor tables and chairs and tiki torches and music. I didn't get to Traders Sam's at Poly but I've heard its great and there was always a wait to get in after 8pm (no kids allowed after 8pm).
For transportation, Poly wins for sure (I love the monorail as MK is our favorite park) but the boat to MK from WL is really really nice. Esp. on the way home.