I use the netflix app on the oppo all the time and have no issues at all. I am going wired with FIOS, not wi-fi..
I also have a roku HD and there is no difference in the performance of the oppo and roku.
I hit the 1080 stream in about 10 seconds, it never drops to anything lower unless I pause, then ramps back up in about 10 seconds.
Same on both units.
I'd guess some people may have an internet service reliability problem.