Judo for all the reasons stated above, and IMO it also takes less time to become proficient in basic judo than aikido.
FWIW I also feel that most aikidoka could also bennifit from some judo training. I remember having a conversation years ago with Dan Harden after my 2nd IT training workshop at his home dojo. I told him that I really hoped the IT stuff would help me really throw a resisting partner. Dan's response "if you want to learn how to actually throw someone go find a judo dojo." I did, and much to my pleasure and the displeasure of my fellow aikidoka he was right :-)
Well the take home message could be that IT wouldn't help you.
Judo randori takes very little intuitive understanding - you can do it and reap the benefit right away. Take away that type of resistance training and you move into the realm of faith - confidence takes more time.