In the time I've been doing aikido, I have continued to wonder (wander?) on and off about the 'effectiveness issue' despite the fact the reason I started was nothing to do with self-defence. However, because aikido is a budo, the questions keep cropping up:
How would I react if attacked? Would any of these techniques hold up? How would a real attacker act differently to an uke? (attacking someone without bowing first is in my opinion just plain rude) How fast could I run away? etc. etc.
Rather than try to answer that lot, I just focus on other aspects of training, and get on with it.
The only comparison I have of any value isn't with other people or even other arts; it's how I would have been had I never started aikido in the first place - and like Wynand, I think this version of myself is preferable if push comes to shove, ahem - I mean tenkan.