The best Blu-ray players now support Ultra HD TVs. They have 3840×2160 resolution, better color output and don't compress streaming services that much.

The best Blu-ray player: Sony BDP-S3500 ( Has the best user interface, a wide varietyof streaming content, great Blu-ray picture quality.)
The second best Blu-ray player: Oppo BDP-103D (plays any disc, from DVD to Blu-ray, great 4K upscaling)
The best affordable Blu-ray player: Sony BDP-S1500 (does the job - plays the disc, also plays streaming well)