I apologize for not reviewing all of the posts beforehand (& inadvertantly echoing another person's post) in advance.
As for my experiences with the Palladium system:
RIFTS was the 1st incarnation of the universal system seen in all of the books. While it has remained relatively the same in the various games, there was enough differences between the games to make them not so easily to interchange.
Nevertheless, Palladium games, w/ RIFTS as the primary example, has a "newer is better" mechanic in the games, releasing new, better, more powerful mechanics/rules material in newer supplements. In essence, it's unbalanced; and frankly, balance is important. Why?
Because EVERY player should feel like his/her character is worthwhile, despite what race or OCC or RCC he/she selects. Believe me, it sucks to play a RIFTS Vagabond alongside a Glitter Boy, Juicer, or other uber-OCC. It often feels like you're penalized for not selecting the most powerful race/class choices out there, even though you may have a cool character concept for another, not as powerful OCC. If a game is genuinely a game just for fun, then shouldn't a player be able to have fun playing any race/OCC/RCC in the game, and feel as equally important/viable as a character alongside the other PCs? IMHO, the Palladium system (especially RIFTS) severely lacks this.
Palladium has killed game interest for me rather than generate it. I can honestly say that Heroes Unlimited (along with the TSR Marvel d% game) killed any interest I may have or once had for any supers game that uses a dice-based resolution mechanic. I also dislike the "anything & everything" sorts of settings ala RIFTS, because of my experiences with RIFTS.
IMHO, it feels like Palladium games tend to market on the idea of individual player enjoyment of a game rather than group enjoyment of a game. And, to a degree, IMHO, I think the most extreme fanboys/dedicates of the Palladium system fit into this niche.
IMHO, it seems that Palladium FRPG (and in a way the other lines that Palladium produced) were made as an alternative to D&D as the time--it had the "armor as damage absorption," "use Dex to hit in melee," "collective weapon proficiencies/WP groups," "spell points," and other such ideas which people have mentioned for D&D at 1 point or another. But, like the D&D of old, it was a slap-together system of different methods & mechanics for different means. It used different XP charts for different OCCs/RCCs as its "balance" method. And, it had its inconsistencies. D&D, White Wolf's WoD, and GURPS, to name a few, have really grown over time, getting better at what they do. Palladium, OTOH, (IMHO) really hasn't. It's made itself "universal" by using the RIFTS system in all of its games now, but it still clings to a very fragmented, fractured, pieced-together system. It feels like the messy attempt to try to pander to all sorts of gamers, gaming styles, and games with one system (mixing the heroic action of D&D w/ WW's story-based games w/ GURPS strive for realism), and failing in the attempt.
Well, IMHO, at least.
