I have done Poly CL for 7/4 the last two years. Have stayed CR CL several times as well, but not 7/4.
It is really hard to beat Poly for special days like 7/4. I prefer the head-on/straight angle facing the MK. CR is great too, it’s just off to the side.
For 7/4 they shoot off fireworks from the middle island in the 7 Seas Lagoon. That makes fireworks viewing from Poly even better.
They also park the Electrical Water Pageant barges out front of Poly for the show audio, in addition to what runs through the Poly ground speakers.
With a Poly TPV room you will likely opt to watch from your room, but in case you don’t they set up a reserved section with chairs for just CL guests on the beach.
A couple of pics from a Poly CL TPV room from last year in case they are helpful.
View attachment 409803
View attachment 409805
When you combine the lounge, the location of the Hawaii longhouse, the viewing angle, reserved viewing, and overall resort vibe, it’s hard to beat Poly. The resort itself (and the CL building/lounge) is very busy on these special days, but to me it’s a lot of fun.