Having practiced Judo for many years, my personal experience is that Judo and Ju-Jitsu are unbeatable once a grappling hold has been established. I don't think the average aikidoka has enough experience in grappling to be able to do anything useful.
The advantage of aikido, the way I see it, is minimizing the contact with the opponent, and keeping distance, even with armlocks or throws which in opposition to Judo are done from a safe distance and do not require body to body contact.
This I believe leaves you free to worry about some other attackers while grappling in the mud with the other guy will leave you vulnerable to multiple attacks. Also this gives you the option of running away which would be more difficult while grappling.