I would go for the Emotiva.
Here are my reasons. You can evaluate how well or if they apply to your needs:
1) From the AH review: "Clean tight sound". I think this is an attribute of an acoustic suspension or sealed design, which the Emo is the only one listed.
2) Better the devil you know - Simply that it has been reviewed by AH so you know that it has no major failings, performs well, and has been pushed to the limits - "the Emotiva Ultra 12's limiter did a nice job of preventing distortion" which is really one of the most important attributes of a sub. No matter how it sounds otherwise, you don't want a sub that breaks up or distorts when you push its limits. Apparently the EMO does a nice job of regulating the LF SPL to avoid this. (this should never be an issue with music).
3) Smaller size increases placement options - As long as it gives you the output you need (and it does well on this count).
4) Warranty - I didn't actually check the others, but the Emo has a 5 year warranty on the amp and driver. Typically a sub will have 1-2 years on teh amp and maybe 7 or 10 years on the driver. However, IMHO, the amp is the part that matters - speakers just don't die near as often as electronics.