All the BD movies I have (only 4 to date though) have played 1080i through the component cables to my 3805. The BD-P1400 does have the option of selecting the output resolution from 480i, 720p, or 1080i when using component in the video setup menu. When using HDMI the 1080p option is available. Currently I have 1080i selected. (The player has to detect the HDMI return signal from the HDTV in order for it to turn on the 1080p option.)
I choose the BD-P1400 over the S300 because the BD-P1400 has better sound options. It can decode Dolby Digital Plus, Dolby True HD, DTS, and DTS HD. The S300 only has Dolby Digital Plus and DTS decoders.
I think True HD and DTS HD can only be outputted through HDMI to a compatible receiver (which I will get in the future). Currently I am down-mixing True HD and DTS HD to Dolby Digital bitstream and DTS bitstream to play through the digital coax output going to my 3805. The down-mixed signal sounds better than regular Dolby Digital and DTS from regular DVDs.