I recommend Mercy. 
 ...well, well, well! Some Aussie angel book just captured my heart. =) 
 I've been eyeing Mercy for a long time now. So upon finishing Mercy's story, I felt awesome. That basement face-off scene with the bad guy? So badass! 
 Mercy woke up to find herself inside Carmen's body, disoriented (again). It amazed me that while she has no idea on who Carmen is, she's so calm and collected, thinking on how she should impersonate Carmen. Oh, Carmen is still there, a hovering presence inside her own body, but she can do nothing while Mercy play body-snatcher. And at the same time, Mercy's trying to recall her past 'lives' - the bodies of the girls she inhabited prior Carmen - to figure out who she really is. 
 Mercy 'loves looking' at beautiful things, and I found that charming on her character. She's also not afraid to be condescending. Definitely not a dull moment with Mercy! Especially the first time she met Ryan. Ha! My girl got balls. :) 
 The angelology was alright, but it was a solid take on Lucifer's fall. The angel theme was halfway elaborated because the mystery element overwhelmed the story. Still, it was okay! Because of Ryan's adamant refusal to admit his twin sister is dead, Mercy found something else to brood about besides her f*cked-up existence. And of course, being a crime/suspense junkie that I am, I was so delighted on how the story unfolded. 
 Mercy is to my great liking. Not too paranormal, more like a crime/suspense story with a tinge of angelic. And yet, when Mercy had to embrace her true identity as an angel, it was so darn impressive!