I much prefer
Marceline. It flows better, and avoids the icky -cella ending.
Marcella sounds villainous and contagious. I wouldn't be surprised to see it on a Disney villain or an newly discovered virus.
Personality wise,
Marceline sounds quiet, pretty, and artistic. I wouldn't use a nickname, but if I had to choose, I'd use
Ellie.
Marcie sounds dated,
Celine is its own name, and
Ella is too trendy.
Marceline still wins out over
Marguerite and
Marcelina.
Marcelina is too flowery, and I just don't care for
Margaret or any of its variations.
http://www.behindthename.com/pnl/177263