Palladium Books' flagship RPG is RIFTS, and a lot of that accidental brilliance can found therein, but it is a mistake to avoid their other games. I mentioned Palladium's fantasy game the other day, but its science fiction games are no less full of earnest brilliance. The latest one is Splicers, a one-book game that's best summed up as "Terminator meets Bio-Booster Armor Guyver by way of Dune."
The problem is that this summary, while accurate, is a pain in the ass to make work at the table because the book's content is so horribly laid out that you had to wonder if Palladium used a retarded rhesus monkey to do the job. The actual rules are in the back of the book, not up-front where the reader actually needs them to be in an instruction manual (and that's what a tabletop RPG book is: an instruction manual). The rest of the book is similarly amateurish in its presentation.
Yet, once you do get your head around it, this game is a brilliant mashup and there's plenty of potential for dynastic power plays (D&D's original endgame), hot-blooded action against implacable foes using exotic weapons (your default play structure: power-armor unit fights Machine forces to achieve an objective), and the chance to employ the old-school mode of running a game laid out at Ars Ludi: the West Marches model.
The catch here is that the setting isn't that friendly to standard D&D-style play structures. It lacks critical elements that make tabletop RPGs easy to run (specifically, the Anarchy element is lacking; see the link), because you're not going to get the fun stuff without being yoked to an infrastructure controlled by a warlord more powerful than you and therefore there's Oaths of Fealty involved (and you had better believer those oaths have teeth; this is one of those settings where exile is a death sentence). Medieval Mindset in Miraculous Military Machinery is a good summary.
But, if you're willing to abide by those boundaries, you can have a hell of a good time. You just have to work for it, especially as the Game Master, because you're taking half-explained (and half-explored) ideas and having to finish fleshing them into solid complete constructs for use at your table. It helps if you're familiar with the source material that this game draws from, and the concepts as used therein, but it's not necessary. As a player, you've got to accept that your man isn't independent or autonomous; you're better off taking the mindset that you would in playing King Arthur Pendragon than you would with D&D. You act on behalf of your lord and your clan first and foremost, and on behalf of your nation (Mankind) second, when fighting the Machine.
Because this is so poorly presented, lots of people pass Splicers up; most people will never work for their entertainment, and this game does require some to be done to get the fun out of it. That's a mistake; give this game a go if you like your mashups filled with action, romance, giant robot combat (and you don't want to play Mekton).