I see good things in both of these.  I like Alexander's rendering but
will try to explain in more detail how I feel it could be improved.

In gnokii's version, the trails of the exploding particles have a
softer, fuzzier look.  In Alexander's, they are very fine streaks with
what I would call a higher energy -- meaning (at least to me) there
are very abrupt contrasts between one color/brightness and another.
To my eye this makes for a more distracting background, when I think
the right goal would be a beautiful but subtle background that doesn't
make itself too noticeable.  Also, the center of the fireworks are
very bright, again making for possibly some excess distraction.

However, overall Alexander's rendering does have a great feel, and
perhaps softening or blurring these exploding trails outward from the
center of each firework would help reduce the energy somewhat.  I'm
not sure how much the brightness of the center of each firework could
be adjusted without sacrificing people's ability to know what they're
looking at.

I wish I had the skill to do a version based on what I'm talking
about, but I don't.  But I hope the explanation was helpful to someone
who does!