I take it that you're using an ethernet connection from the bridge to the player, I would check the download speed at the bridge by plugging in a laptop to the same ethernet port used by the player. speedtest.net is a site that I use to measure my connection speed.
Netflix states that an internet connection speed of 5 Mbps is required for HD streaming only for those titles available in HD for others I would guess a lower speed would be adequate for highest quality streaming. In the past Netflix had indicated 2.2 Mbps for the best available streaming quality for SD titles though this statement no longer appears on their site. They now state that the best possible video quality will be chosen for the current connection speed.
I have a Samsung BD1590 and just got it to stream video from Netflix.(after jumping through a few hoops to get past the gateway ping failure) I am using the slingbox turo to bridge from my router to my player, but the video quality is not very good. Is there any way to improve the quality of the streaming video?