The power figures are a complete work of fiction. It's the same with any of these one-box audio systems. If you're getting a couple of hundred Watts out of either when running properly at full volume then you'll be doing well.
Of the two systems, I would favour the HT-RT4. Here's why...
1) History shows us time and time again that in audio systems with a built-in disc player that it's that disc player that's the first thing to go wrong. When it does, you then find out that either it can't be repaired, or they want to charge you through the nose
2) We stream and watch more stuff from Sky/Virgin/BT than we buy discs
3) Where we do want to play physical media, there's a fair chance that a console will do just fine. Failing that, standalone Blu-ray players are cheap and far more reliable than built-in units
Beyond this, neither system offers a lot of physical sockets to plug stuff in directly, and even if you could, both sets fall short on the sort of HD audio processing required to make the most of a the great quality of sound from a typical Blu-ray. I'm not talking about Dolby ATMOS here, just the high quality sound from a normal Blu-ray disc.
What your BiL will end up doing then is routing everything via the TV, and then pick up a basic audio feed out via either HDMI ARC (if his TV has it) or via optical. That's convenient but a bit of a quality bottleneck too. Having said that, at this level, its par for the course.
Two other reasons for choosing the HT-RT4:
First, there's no money wasted on the disc player, so in theory there's more money Sony's manufacturing budget for better quality speakers.
Second, the sub is going to be contributing a lot to the sound of voices and music. Its better then to have the sub near to the TV and centre speaker position so that the blend between the centre and sub works better. With the RT4 having its connections on the sub then it naturally lends itself to a position closer to the TV.
