This is a great expansion, in addition to what some others have said, you can pretty much make anywhere in Europe Muslim if you know what you are doing and also have the Old Gods expansion. Just go down to Muslim Africa, raid some coastal cities, and you have Muslim concubines you can use to convert to Islam. Both fortunately and unfortunately, being a Muslim in Nordic lands provides for a "target rich environment." But yeah, you can also be a normal Muslim and just enjoy the different Muslim gameplay mechanics.

Any DLC that makes an entire group of nations playable is a DLC worth buying. And a DLC that makes the entire southern half of the map playable is definitely a DLC worth buying. The rules for playing as a Muslim ruler are slightly different, and initially quite challenging to adapt to. But it's worth it once you get it under control.

Are you bored of being a nice christian ruler? You wish the pope would just stop messing up your plans? Get this and enjoy a totally different perspective and style of play. I know that must have sounded like a bad car commercial, but really, you get to play the "other" side, you get to experience a new set of challenges.

It takes the whole perfection and joy of Crusader Kings 2,but now it allows you to play the muslim faith,with re-made UI fit for muslims and new game mechanics,this is just a MUST have expansion for CK2.

This DLC enables the player to play as any Muslim character on the Crusader Kings 2 map, thus meeting one of the most requested features by players of CKII. The Sword of Islam (SoI) also introduces mechanics in an attempt to model medieval Islamic government. Mostly this is successful as you get into the mindset of an Islamic emir, both trying to win prestige and piety while attempting to manage your unruly and all too often murderous kinsmen, children and wives. For me, as a great lover of the base game, this DLC did add a lot by added more playable characters and introducing some slightly different mechanics. On the other hand it doesn't radically alter the gameplay by using SoI to play a Muslim character. Nevertheless, if you loved the base game of CKII, then SoI is well worth spending the money on.