mslide, I think you're off on a couple of things…
Plex, however, gives you a lot more options at the cost of not being able to use devices like non-jailbroken Apple TVs. A big reason why you hear so many people around here wanting an "Apple TV app store" is because they want to run Plex on a non-jailbroken Apple TV.
You can use Plex with a non-jailbroken ATV by way of AirPlay.
That could mean sacrificing audio/visual quality. Some people (I used to be one of them) get immediately turned off at the idea of having to sacrifice audio/visual quality, even if they can't tell the difference. Plex, and other HTPC solutions, allow you to play a ripped Blu-Ray without having to re-encode anything. You just stuff the un-altered audio/video tracks into an MKV. Thus, you retain the audio/visual quality of the original disk.
Plex is a client/server solution. You run Plex Media Server on a capable server/desktop computer that is always left turned on. If you use your iPhone, for example, as your "client", and want to play a high-bitrate Blu-ray MKV rip, Plex Media Server will do on-the-fly transcoding to downconvert the video to something that can be played on your iPhone (and iOS-based Apple TV), which you can then AirPlay to the Apple TV. If you have a capable desktop PC running Plex Media Server, the resulting picture quality should be similar to what you might get if you had used something like Handbrake in advance to downconvert your movie to an iTunes-friendly MP4 format. The Handbrake method will yield better picture quality, but for many people who aren't obsessed about it, the quality can still be very good. And the advantage is time savings. The Handbrake approach will require that you dedicate extra time to do that up-front conversion.
Also, the Plex approach allows you to have a mixed environment in your home where you might have a client that is fully capable of playing back that high-bitrate Blu-ray MKV rip without the need for any on-the-fly transcoding. That's the case with me. I have my main Plex server in my bedroom connected to my TV, and in my living room I have an Acer Revo nettop PC (Intel Atom, NVIDIA ION GPU) which is connected via ethernet, so both of those play my Blu-ray rips as-is, in perfect quality. But thanks to Plex, I can also choose to play them via the Plex iOS app on an iPad or iPhone or one of those devices AirPlaying to an Apple TV where Plex will do its magic and do some on-the-fly transcoding/downconverting. Again, the resulting PQ can be surprisingly great.
Plex also lets you do things like record TV shows. For many, that's reason enough to use Plex. I stopped recording TV years ago though.
I'm not sure what you're referring to here. Plex doesn't support *recording* television shows. It will, however, let you stream previously-recorded TV shows that you've got stored on your central computer. In my case, my Plex Media Server is running on a Windows 7 machine where I also have Windows Media Center running. It's more convoluted than I'd like, but I have it set up so that shortly after a TV show finishes recording (by Windows Media Center), an app will rename/move the TV show, and then Plex Media Server (shortly thereafter) will see that moved TV show file and expose it to any Plex clients I have in my house. So I can play TV shows that I've recorded 30 minutes or more ago, but I can't play live TV. Still, it's pretty cool.