The effect of speed on the perception of rhythm is a very subtle and complicated matter. Well, it is for me, but of course it could be simple while I am dense. One of the more obvious examples is the syncopation in ragtime. Above a certain critical speed a rag begins to sound like a uniform, albeit rough, stream of notes because the listening mind starts to chunk groups of notes together. Exactly the same thing occurs in classical and unsyncopated music only it is less noticeable. I was discussing this point a couple of weeks ago with the wonderful ragtime pianist and composer, Brian Keenan. We both lament the recent resurgence of what he called a "faster, louder, sillier" mentality in piano playing, particularly ragtime. The early composers, Scott Joplin, James Scott and others, took pains to write "Not fast" on their scores for the good reason that fast playing produces a uniform stream of notes and flattens syncopation.
Even though there is little emphatic syncopation in your piece, a flattening effect is produced as speed increases. I can well understand your preference for the slower example.
I think I shall try the reverse technique with some of the horrendously frenetic passages in my improvisation and slow them down. Now that might well teach me a thing or two.
Topic: Meditation. A keyboad experiment in tempo manipulation