In reply to ellenclimbs:
Hi Ellen, for my two pennies worth: both are good quality, good value, durable and safe women's all-rounder harnesses. What do you want the harness for? Indoor climbing, trad, sport...? The Luna has 4 gear loops - your daughter may not need the 7 that the Puma offers - and is comparatively lighter than the equivalent size Puma. However the Puma comes in smaller sizes than the Luna, which might suit your daughter's shape better (I'm 5'3" / size 8 and have an XS Puma). Like Jon says, it would be best to try both on in a shop if possible. I've reviewed the Puma here:
http://www.ukclimbing.com/gear/review.php?id=2978
Size comparison:
Puma XXS: waist 50-68cm, leg 40-52cm, weight 390g.
Puma XS: waist 59-80cm, leg 50-60cm, weight 430g.
Puma S: waist 67-91cm, 55-65cm, weight 480g.
Luna S: waist 60-71cm, weight 410cm.
Cheers, Sarah