Myraj
On paper sony and reviewers more or less state that, but no the S550 has a substantially heavier structured chassis and transport
IN the box of the S550 you get the USB card included
And even though the S350 is listed as 2.0 profile capable, thats exactly it, its "Capable" but I guess you have to go and get a USB card and do the firmware updates as it will not be setup out of the box. There is little info on this but seems to be true
Beyond that they both seem to deep color mode if your display is capable which mostly you need a pretty advanced and new panel to do it, and both have options to actually change your Data out if using the coax or toslink to priority settings and picking 16/48 or 24/96 format
Other than that the S550 is even a little faster loading, but I don't know if this is simply due to it has the Blu ray 2.0 profile firmware already loaded or not, but I assume even though this is for online menus etc.. that it could be effecting the Blu ray disc load menu as well.. Not sure..
Oh and the S550 has a nice Backlight on the remote, the s350 does not.. So there are a few upscale features just in build and performance it seems beyond just the true HD surround 7.1 modes etc
Also the Entire S550 body is coated in a Very thick and hardened Piano laquer finish (Think Pioneer Elite series) and the S350 is in the basic generic black chip paint. The S550 is a taller and heavier unit however, so for compact and basically the same video performance the S350 may be better for some..
For those looking into the all out performance and the perks of better build (quieter transport) etc
The S550 does that as a nice step up, but obviously is not really marketed that way. Also as you state the S550 does have 7.1 analog outputs, however also has capability of all the newer surround true dolby etc. formats native to blu ray, the s350 does not decode this HDMI OR ANalog.
