I'm very much a person who believes that system matters, so it's really a matter of choosing the right game for the right job and finding mechanics that support and enable to mode of play you're going for. Sometimes this can be the same rules system, with different tweaks, changes and house rules.
Over the years, various systems have tickled a particular aspect of my games and have been explored.
Heavy Gear: The system used for Heavy Gear scales brilliantly, allowing you to move seamlessly between vehicle/mech, starship and personal combat. This is the one area in which the system truly excels and it is a shame that Dreampod Nine's games haven't retained the traction – and crossover audience – that they deserve.
Feng Shui: Feng Shui's stunt mechanics loom large over many subsequent games that go for narrative style emulation over realism. One of the ur-examples, Feng Shui rewarded, rather than penalised you when you did cool martial arts or kung fu moves.
Call of Cthulhu: The Sanity system, especially as it interacts with Mythos lore really works as a sort of 'devil's bargain'. This central tension in the system raises it above merely being a workmanlike and somewhat realistic percentile system.
Blue Planet: Reverse order initiative with interrupts just makes so much more sense than most other initiative systems, albeit it the case that it does slow things down.
Mind's Eye Theatre (1e): An almost purely narrative mechanic based on descriptors. This and Over the Edge inspired the take I took with The Description System that I used in the Neverwhere RPG.
Hey, thanks for stopping by. I'm an independent RPG (and other games) designer and author. You can check out my stuff via the links at the side of postmortemstudios.wordpress.com. If you feel so inclined, after a look around, you can support me at patreon.com/grimachu, Minds.com/grimachu or steemit.com/@grimjim. Questions and queries are welcome, remember, 'Nullius in verba'!