As tonka confusingly said, there's a possibility the current girl on Estelle's profile is not the one that's been widely reviewed here.
Why I'm uncertain is because
there's a review of the profile dated 26/11/2014 that mentions "brown hair now instead of black".
Fortunately, there's a way to tell who she is.
In my review of her, I had the foresight to attach her pics then which showed and mentioned the star tattoo on her hips.
So all we need now is for the most recent person who has seen her to confirm if the girl they saw still has the tattoos.
Moving on to your question ... I haven't seen Chantelle but, in terms of their differences, her reviews do mention that she's a bit more subdued during sex.
And I've been told, while commenting on her attractiveness in another recent thread, that she may not be as attractive as I initially thought she would be. Probably a 7 vs an 8, but beauty is subjective.
Having said that, I don't think you'll regret going with either one. Actually, since they're both among the best VFM WGs around, why not try both and give us your notes on them?