Setup:
Panasonic PH9 42" plasma with a fb8.. hdmi blade
Speakers: 2xB&W FPM4, 1xFPM 5, B&W pv1 sub

The PQ from my cable-box(STB, outputting RGB,576p) is not good enough and will have to wait about 3 months for HDTV. I want to improve the SD-picture.(and have decent sound ofcourse). Picture shows a lot of fizzling around subtitles and logos, and shows some videonoise.

Option 1
I could buy a sony 5200es for upconverting, i read a few contradictionary reviews about the upscaling of the 5200 or buy a yamaha 2700. I would have to connect the STB by a scart-component converter to the av receiver.

Downsides: quality of scaling? no scaling/deinterlacing with hdmi in the future(when i get a HD-DVD player and HDTV STB)

Option 2:
I could buy a dvdo HD+ scaler and a marantz 4001/onkyo 604. I would have to connect the STB to the DVDO HD+ and audio from the STB to the onkyo/ marantz bij coax digital. I would connect the dvdo to the plasma by a dvi-hdmi cable(currently have a fb8 hdmi blade)

In future when i get the hd-dvd and the hdtv(HDMI) STB i could connect the hd-dvd player and the STB by hdmi to the onkyo 604/marantz for sound and run a hdmi-dvi cable from receiver to the DVDO HD+ and from DVDO to plasma with a dvi-hdmi cable.

Which option is best for PQ and decent sound?
i can get the onkyo 604/marantz 4001 for about 350 euro in the Netherlands and a slightly used dvdo HD+ for around 600. That will cost me about 950 euro.
I can het the sony 5200es for 920 euro and the yamaha 2700 for 1200 euro

Will the DVDO HD+ beat the sony 5200 as a video processor?