This game is NOT a Counter strike clone. I was cal-invite, cevo-pro, and scraped in cpl and played for united 5 gaming all for counter strike and also wolfenstein (went to quakecon and scraped for enemy territory). But lol at the counter strike comparison. Definitely not a good one. Like you can -blam!-ing knock a wall down in siege. You can pilot a drone, there are specific classes, sensitivity is different (because it isn't a PC game), the customization isn't nearly the same, guns (different), gameplay (different), only thing similar are the game modes. And there are only 3 lol.
Both games pit two teams of five against each other with various objectives. Matches can end in both games by completing the objectives, or eliminating the other team. Certain objectives are practically the same in both games, hostage rescue and bomb planting/defusal. There are no respawns and health doesn't regenerate. Both games have incredibly quick times to kill. Etc.
The game is at its core a CS clone, clearly influenced by GO. Note that I say at it's "core", though. The game built on that foundation is very different to CS.
Besides, a [i]Rainbow Six[/i] game being similar to [i]Counter Strike[/i] is not a bad thing at all, and serves to bring it a step closer to the series tactical roots.