It sounds like a primary consideration is fireworks viewing. I don't like the fireworks view from BLT - even though you're closer, you're at a bad angle. You end up seeing the low-laying fireworks by the castle, and then the high-flying fireworks by Bay Lake. It ends up feeling like you're watching two competing fireworks shows. Here's a
video I took from my balcony back in January.
Poly, on the other hand, gives you a perfect head on view where the show appears as its intended. Don't let the distance concern you; you can see everything just fine.
And instead of spending a small fortune on theme park views, both BLT and Poly have public areas that are great for fireworks viewing.