I was originally into the Transformers back in 1984 when I was 6. Around the time I got into high school, I kinda forgot about them (1992-3). After seeing the movie a couple of times, something in my inner child has awakened (and my wife has discovered me to be a huge dork, but she's OK with that). I had maybe 30-40 Transformers over my time, and I think most of them are still at my parents' house, though I have no idea for certain. I oughtta check that out, though...I had a full, complete Defensor, Superion, and Devastator in that bunch...I've looked up every character profile on wikipedia (before I found this place, at least) and I put together a personal list of what I remember having and it numbers 33. Anyway...
I've gone out and purchased all five movie Autobots:
Leader Optimus Prime
Voyager Ironhide
Deluxe Bumblebee (2008 concept)
Fast Action Battlers Ratchet and Jazz (all I can find around here)
I got them in that order. I expected Optimus Prime to be complex to transform and I was not disappointed. Even with the directions, I think my first conversion to semi mode took around a half hour. Back to robot mode was much easier, and subsequent transformations have been much easier.
What I was not expecting was the complexities behind Ironhide and Bumblebee. Bumblebee's head popped off and his body popped at the socket, and fortunately they both pop back on just as easily. It took me a while to figure him out, maybe 15 minutes or so. Ironhide took almost as long as Optimus, though...I couldn't figure out what that 180-degree turn was all about; he's so dark in color it wasn't obvious to me that he had the little plate where you do the rotation. As a result, his feet were backwards. The hood/doors/windshield assembly gave me fits, and that dumb little armor plate that swings up with the little plate on the top keeps folding down.
I don't judge any of those three to be toys I'd give to a 6-year-old kid as I was starting out, or expect them to be able to transform them on their own.
Then I got to Jazz and Ratchet, as the only versions of them I could find were the Fast Action Battlers. These are both more like my old-man speed and more along the lines of what I remember as a kid. Especially Jazz, where the front end of the car folds down. I mean that both in terms of complexity and design. Ratchet is obviously different (considering IIRC Ratchet and Ironhide G1 toys didn't have a head) from his origins, but still, they're both very straightforward. I'd give these to my kid, should such a thing exist in the near future.
An aside: I'm rediscovering my youth and I'm also starting to discover what I'd been missing. It's all wonderful. Embrace me!