I am by no means anything more than a amateur (and that may be stretching it), but I really like the first one and I think the lighting and exposure are pretty good in that shot. The second one does look underexposed and a bit too busy. I have had the exact same problem (too busy) with macro flower shots as I also use a screw-on close-up lens (Canon 500D) instead of a proper (read expensive) macro lens. On really small flowers, you just can't get close enough to isolate a single subject and I have yet to take a shot of a bunch of flowers on a branch that I thought turned out interesting. My solution has been to shoot larger flowers and really try to isolate a single subject. You can check out some of my "attempts" at doing that at:
Macro Photo Gallery by whiplash23 at pbase.com