Re: Brazilian Jiu-Jitsu *not vs* Aikido
Just to settle your confusion, these days I try to do formal BJJ once a week (mixing up gi vs. no-gi) and then seminars whenever possible. I work out with grapplers from wrestling, judo and sambo whenever possible. I have a base in boxing, judo, wrestling, sports karate (blecch) and humorous attempts at kickboxing (not my game, I know it, but still think there's benefit to training it). I try to brush up on these with other practitioners whenever possible, but am primarly committed with my dojo's aikido program (as my long term budo study).
I started training in martial sports when I was 5 (judo) and continued in one form (judo - wrestling - judo - wrestling - karate - wrestling) or another through college. I am now 32. I have different training goals than martial sports, but still recognize the skills they build and polish. I don't claim expertise in any of them, but still like to go play with people that are.
When I spar with people in specific martial sports, I usually already have some sort of a base in a version of their sport (if not their sport). So, depending on the sparring paradigm, I'm not going to backpedal from a clinch or takedown and don't mind trading hands and feet. In other words, I'll shin kick, jab, hook, bodylock, shoot, submit with the next guy. I'm not gonna try to tenkan, spin away from trouble or panic when things don't look like aikido.
Because each sport trains towards certain goals (even different gyms within the same sports - don't believe me? Go visit three different non-affilitated BJJ schools in one week), the degree with which they're congruent with how I train overall can sometimes throw me off. But it goes back to what Don Magee said (and I've already stolen this as a saying), when you're training a specific drill (no matter the art/style/sport), you work on the goals of that specific drill, regardless of what you "think" you know.