I watched the first two episodes dubbed on Funimation's site. Not bad, though I would have expected a slightly "younger" sounding voice for Holo (man, is that hard to get used to). I, too, felt the lines were more "casually" delivered and not like they were reading from a script in a recording booth - Lawrence's interaction with the guard in the first few minutes of ep 1 being a good example of that. (Chloe's "for God's sake!" at one point was another.)
The one thing that grates on me, and I don't know if it's a case of getting used to 'Holo' or not, is the pronunciation used, particularly the long 'o' sound of the first vowel.. it sounds like they are saying "Hoe-low" all the time. I always considered the first 'o' to be a shorter, softer vowel, as in "Huh-low" if you will. We'll see once I get the DVDs if it grows on me or not.
All in all I do like the dub, especially since I think I can convince a bunch of friends and family to get into this show now that it's available in English.