It's kind of a slow day so just for fun and discussion I thought I'd post a few things that I think Sony did/does well.
The PSOne, Vita and reportedly the PS4 are easy to develop for. The less time that developers have to spend battling the system to get a game to work is time that could be spent on quality control, improving things or even working on extra content.
Sony is the one company that united multiple companies within the industry against software piracy. Other companies made their own efforts against piracy but Sony took the lead for a coordinated effort.
Sony was the first company to include a second analog stick which is often used for camera control. This fixed a lot of problems in early 3D games on N64 and Saturn and even PSOne.
Sony's first party studios are generally very good. I do think we hit a period where Sony was cranking out so many titles that their quality control took a hit but for the most part they have a lot of talent there.
I am a big fan of the "Play-Create-Share" concept Sony uses in games like Little Big Planet, ModNation Racers and Sound Shapes.
While it is not my favorite controller, the DS3 controller is well suited for a variety of game genres.
I like that Sony is willing to experiment with different pricing models. It is nice to see that somebody realizes not every game needs to release at $60/$40 for home/handheld consoles.
While the quality of the games offered on Plus can be hit or miss, the program itself is an excellent idea and it is good to see a company thinking outside the box like that.