I bought a few Shadowrun books out of curiosity. I would really like to try playing, but I would not want to try running it. Shadowrun has great lore though. The most unique corporate dystopia I have ever read. It was futuristic modern fantasy written in the 1980s and they never made a major update, so some of it doesn't track (Japan is the economically most powerful nation on Earth). The game rules are quite complicated. And that's just basic combat. There are also cyborgs, mages, riggers, technopaths, and adepts with unique abilities with their own class specific rules. I like my system (which is 80-90% stolen from White Wolf). It's simple and easy to understand. But no system is perfect. Combat is a little slower to run than it is with D&D and Pathfinder but I am working on ways to speed it up a bit and think noncombat scenarios are very smoothly run.
I loved the Shadowrun lore. The best system I've found for it was a friend who ported it into Savage Worlds. It worked better than I expected.
I'm personally a fan of GURPS. Sure, the GM needs to run a tight ship when it comes to what content is allowed and which is outright banned, and you quite literally need a computer program to create a character sheet, but I've enjoyed a lot of flexibility with both running and playing in many campaigns across various settings.