Well let me be the first in to plug HERO system. Although I'm sure there will be others.
Start Up Cost: well you can do it with just the BBB (Big Black Book). Not sure what the cost is in the US but here in Oz it set me back about $100. It's about 500 pages. But this is just a rule book, mechanics only, no flavour. But it does have all the rules you need and you can build everything with this. Rules for building super powers from the ground up. Rules for vehicles, bases, martial arts, all the stuff of supers. It is also meant as a generic, universal system. So there is space dedicated to rules you may not be interested in. For flavour you will need supplements. You can also just haunt the HERO System boards to get an idea about what is in the Champions Universe, which is free. (That's what I do.)
Supplements: You don't NEED any. In theory everything in the supplements can be built using the mechanics as set out in the BBB. And I'd say 99% of the time that's true. One notable exception is martial arts. The mechanics behind these not set out in the BBB (they may be covered the Martial Arts supplement, I haven't read the new one but they were covered in a previous edition.) Getting back on topic, you don't NEED any supplements but they sure do help. And the fact that the supplements are all very good makes getting them that much more attractive. You can see new ways of bending and shaping the system. And the supplements cover pretty much everything. From NPCs and organisations (I love the VIPER supplement so much it's a little bit wrong), to different genres (Pulp, fantasy, Sci-fi) to vehicles to books dedicated to specific types of characters (the Ultimate Brick and the Ultimate Martial Artist for instance.)
Style: Points based. Experience is doled out in character points, characters go up in power by spending them on their powers, stats, base, followers, etc. They can save up to buy bigger stuff or just spend it in dribs and drabs. When designing characters initially you can get more points by taking disadvantages (classics like vulnerability to fire or being hideously mutated, social disads, physical disads, psychological disads.) In fact the system strongly encourages disads. and role playing with them.
Ease of system. Easy it aint. This is because it is attempting to be universal and flexible and because it is very granular. VERY granular. The character design can be extremely complicated if the player so desires. It doesn't have to be. And to begin with I think everyone would benefit from playing simple characters. Bricks and flying energy projectors are simple enough. Get more complex as system mastery increases. But if you wanted advice on more complex builds put a request on the HERO forums. You should have a dozen or so various builds within a few hours. These HERO system players are crazy.
As for the actual play: When I was first introduced to it years ago my friend said it was a great system to encourage role playing, because the combat system is so difficult to use.
I think that's an overstatement, but not by that much. It is pretty complex but this is enables a great deal more flexibility. Which I guess is the trade off. On the plus side it's much more consistent and better set out than, say, D20.
Range of Power. This is where it shines. You can do anything. Usually in several different ways. Power suits? Check. Magic? Check. Street Level?Check. Galactic Heroes? Check (there's even supplements for all these things.) But you have to dedicate the time to learning the system well enough to be able to make it do these things. (or buy the supplements of course but who has all this money I ask you?) And it all scales pretty well. Something to note: Unlike most other systems the powers are not defined by special effect (there is no section on fire powers for instance) but by mechanic. You would buy a flaming sword as (for instance) an Energy Attack with no range and define it as a 'flaming sword'. Someone else could by a 'light sabre' for exactly the same point cost and just define it as 'plasma' or whatever. This means that players usually need to know what they want to play before sitting down to design the character.
Setting: I believe City of Heroes is in the the MMO for HERO. But I could be wrong. There are plenty of supplement books that define the 'official' Champions-verse. (both old and new, the previous editions are similar enough that you can use characters from them without much mucking about.) But the BBB is generic. You can set the game anywhere you like. Friends of mine just finished playing a Marvel Mutants campaign. I've been designing a hi-tech game set in something resembling the Bubble Gum Crisis -verse.
Potential: Again this is where it's great. You can punch someone through a wall, lift a battle ship, fly across the galaxy in mere hours, spin a web any size etc. A couple of flaws that come to mind: electricty. It's a bit of a common whinge among HERO players that to design a character with realistic electrical powers just costs TOO many points. (it's the cost of making a power conductive you see.) And common weapons like machine guns, tanks, missiles, etc are all pretty darn deadly for the suggested starting power level. Of course you can just let the players have more points.
hope this helps. If there's anything you would like me to expand on just ask.
cheers,
Glen
