The (I believe) discontinued 50/51 is a fantastic piece set for stereo. I've used that one a lot over the past 5 years or so and have never experienced a single issue of any kind.
A quick look at your link shows that 74/75 is sort of a surround version. Additional items added (surround), other left off (studio monitor, number of input sources, etc.
If the 74/75 provides the functionality you need I wouldn't hesitate. Nice control over sources, quiet, nice build, and well documented (available on line). Make sure to take a look.
Lots of configuration options (dim and talkback level, etc.).