Wargamers everywhere should rejoice to see that after more than aa 15 year absence, Shock Force Second Edition back in prin!
Despite it's age, Shockforce holds up as an excellent example of both a fast and fun platoon skirmish game, and a very useable unit creation mechanic. Shock Force manages to be both alot simpler and faster playing than the 2nd and 3rd editions of 40k it was competing with and at the same time provide a much more tactical game experience. The Roll x dice and keep y dice mechanic that forms the basis for the combat system is intuitive and great for adding variation to the combat experience.
Though it has a great unit creation mechanic that allows players to stat up virtually any figure, Shockforce also includes quite a few complete army lists. Many of these are analogues to 40k armies, but there are also many that come from the sloshing depths of the game designers' vivid imaginations. The only limitation to the game and it's creation mechanic is that it has a hard time accomodating vehicles bigger than light walkers and scout vehicles. Rules for larger vehicles can be easily houseruled (Making 2 statlines for one vehicle is a popular solution) or found at the Warengine Yahoo group.
Personally, Shock Force is my go-to ruleset when I want to break out my old 40k or Void armies and achieve a game that has the vibe and size of those games while being reliably fast moving and fun to play. Don't think that Shock Force is as not-40k game though, the rulset is flexible enough to tailor for a variety of settings and it's even been used for fantasy gaming.
All this to say, if you have an interest in indie wargaming and games that allow you to create your own units you owe it to yourself to check out Shockforce. It's a well-playtested, ruleset that still holds up today.
[5 of 5 Stars!]