malladin said:
Actually a lot of those things you mention are things that turn me off in a game. I can't stand wounds and vitality systems. I'm not a massive fan of straight hp, but the damage threshold seems to work well whenever I've played with it
"Massive damage works fine" isn't exactly an argument against VP/WP.
FWIW, though, if all you are used to is Star Wars VP/WP, you'll find that Spycraft 2.0 is a bit different, but not in ways that make it any less vulnerable... unless that's what you want. There are campaign qualities that change the way VP/WP work.
(unlike WP/VP which just seems to make people even more invulnerable and weapons less varied).
Spycraft 2.0 focuses more on firearms that melee weapons, but firearms are given a lot of detail that makes them varied.
I really like the D20 Modern classes -- I like multiclassing around the basic classes, it means I can play any character I can come up with, rather than (as I usually have to do in D&D) fiddle about with the classes to get what I want.
There's plenty of room to multiclass in SC if you want to. The base classes are a bit more role-based than D20 Moderns.
But if you love the stat based approach, there is a supplement called "back to basics" that has them.
Plus I don't see why you think NPCs don't scale to PC character level in D20M -- perhaps you can enlighten me..?
NPCs
do not scale to character level in D20 Modern. A 5th level ordinary is a 5th level ordinary. You can add levels to it, but you are doing design work to do that. And let me tell you, if there is one thing I hear d20 designers complain about, it's making stat blocks.
NPCs in spycraft have much simiplified stat blocks. They don't necessarily have classes at all, and they have many bonuses that are replace multiple numbers for a PC. NPCs in the book (or as you design them) don't have any modifiers, just a roman numerel describing how good they are.
Then, when you define the threat level (the closest thing to challenge rating in spycraft), you plug in the numbers and the modifiers you get are appropriate to the threat level.
The result is that it is much easier to make NPCs and tune them to the character's abilities.
As for your other points, I'd be interested to know how it manages to have more fun martial arts and why having more actions in combat makes any difference.
Personally, I like Blood & Fists better.

But Spycraft's martial arts is pretty clean, and based around feat chains based on generic specialties.
Combat's not the
big selling point for me, though it does have some modest improvements. It's a bit simpler to deal with, having no iterative attacks and not limiting you to one attack per turn, and replacing attacks of opportunity with a "vulnerability" mechanic. (And there are several d20 modern combat foibles like nonlethal damage and autofire rules I positively hate and always house rule when running d20 modern; spycraft lacks these.) Spycraft's initiative damage rules to re-complicate things, but they really aren't necessary, and I don't use them when playing with beginners.
Bigger selling points to me are the campaign qualities that change the feel of the game to your preference, the dramatic conflict system providing a clean consistent ruleset for non-combat conflicts (chases, interrogation, seduction, hacking, etc.), simpler handling of NPCs, and better action dice system. That some d20 modern designers have seized on to some of these mechanics should be a sign of their appeal.
I'm just about certain that I'll be running Spycraft 2.0 again this year at GenCon. If you are going, I'd be happy to have you in my game.