I don't really know what to say about Sins Of A Solar Empire other than that I've been enjoying it. It's one of the few shining lights in the vast emptiness of contemporary PC gaming.
It's a multiplayer space real-time strategy. I say multiplayer because the single player options are limited to customisable skirmishes against AI opponents. Shipping without any significant single-player campaign is an option that worked for Rise of Nations and it works again here.
The game's biggest claim to fame is its epic scope. You can zoom right in to see the details on your smallest ships as they fire lasers and dogfight, which makes the game look a lot like genre classic Homeworld, or you can zoom out to see the entire gravity well in which you're fighting, the neighbouring planets, the solar system, the local cluster, or in extreme cases the galaxy and neighbouring galaxies.
The game also borrows heavily from Warcraft III for some of its gameplay elements. Your capital ships are effectively hero-class units. They're worth entire fleets of smaller ships, and they gain experience through combat, which allows them to purchase new abilities or level up existing ones.
The third interesting innovation is the bounty system. Each solar system features a "pirate planet", guarded by a fleet of pirates so immense as to make defeating them generally not worthwhile. Every ten minutes or so the pirates will dispatch a fleet to attack a player. Players can pay credits to set bounties on other players; the player with the highest bounty when the pirate timer runs down will be the target of the attack, and the size of the fleet that attacks is based on the size of the bounty.
Players can collect bounty on other players too. Each time a player loses an asset, the person who destroyed that asset claims some of the bounty on the asset's owner. In this way bounties can run all the way down to zero. In multiplayer games it can serve as a way of motivating opponents to fight amongst themselves.
The game doesn't look particularly wonderful when you zoom right in. Ship textures are clean and crisp, but dull, and most of the ship designs are variations on the idea of a flying rectangle. Thankfully the gameplay is the real star, and matches can be customised in a huge variety of ways for maximum fun.
If you're a PC gamer who attends LAN parties or plays online, Sins of a Solar Empire is an easily recommendable purchase. The solo gamer might not get as much out of it, but it remains a fun experience even against AIs.