Mongol....to be or not to be ???

I am an avid total war fan and have all of the total war games with exception of a few add-ons.
I intend to get the penninsula (sp) campaign, Warpath & Alexander from Steam.
The only one I will not have is Mongol Invasion the expansion for STW.
The only way it seems to get this is to purchase either STW Gold edition, STW Warlords or ERA's.
I despise buying games that I already have as that makes my existing copy worthless.
My question: Is Mongol invasion worth it?
PS: I love STW as it reminds me of an awesome real-life (for the time it came out) version of a game I loved and spent many hours on the NES playing called Nobunaga's Ambition.

I would hesitantly say Yes with an IF. ie if you really want to play against the Mogols. It's pretty awesome. AFAIK and it's been a while you can only play against them except in Customs battles. But don't hold me on that

and No, no stand out features. BUT you get a new campaign!!! Wayhey!

The mongols, both to be played and to be faced, are fantastic!

Moreover you'll get even more units for the already existing factions, like, if I remember well, the naginata cavalry, kensai (single man unit able to turn the enemy units in panick), battle ninjas etc...

And it's not just A new campaign: there are something like 6 campagin (maybe i don't remember) everyone of them set in a different period!

It worth to be bought in my opinion! ;)

Moved to Shogun Total War.