The one good thing about BJJ is how much fun people have doing it and how many have come into the fitness world for that reason. When I see people do it in video clips, it looks just like Judo. My biggest problem with it is the connection to MMA but I also have issues with the lack of discipline and etiquette.
90% of Aikido is done standing, or on your knees (suwariwaza). Most techniques end with a pin or a throw, so we stay on our feet almost to the end. A few pins can be done from a standing position.
Aikido is built around elegant footwork, with diagonal and circular movement away from the line of attack. The footwork is entirely based on Kenjutsu as it was passed down from the Samurai. The idea is to get move the attacker from his center and take his balance, even if he/she has his/her hands on you. But you never go to the ground until you are in position for a pin. When you get there, it's over. The pins are built around very painful joint locks. Most are illegal in wrestling and MMA, even though they don't cause injury.
We have a few advanced people who also have backgrounds in Judo or Jujutsu and they will occasionally counter an Aikido pin with a ground fighting move, but it's only done when you leave some kind of opening in your pin and mostly to other Judoka. My sensei is Godan (5th Dan) in Aikido, but Ryukudan (6th Dan) in Danzan Ryu Jujutsu. I'm very careful not to leave openings when I pin him.
A typical night at the dojo might involve pairing up with a partner, throwing him four times and him/her throwing you four times, back and forth for five to ten minutes at a time. You get gassed throwing, because you put all your body into it. You get gassed even more getting thrown, because you either roll or take a hard break fall, and then you have to get back up. By the end of class, the most strenuous thing your are doing is lifting yourself off the mat. I've done it over 100 times in a single class. On my birthday, Sensei through me 54 times in just over 10 minutes.