I've kept both and they are extremely similar species, I find shields to be more attractive so I'd go with them.
Both are pretty large (~8cm), very heavily built, very aggressive, tolerate ranges of temp and humidity, and breed readily. You can't go wrong with either.
I can only speak for the lineola,I have a L5 male thats pretty cool.He reminds me of a cat stalking it's prey.Which leads me to a question anyone know where I could get a L4 or 5 female?
The shields have very cute faces coupled with interesting shields , so judging from what I've seen and heard, I personally would rather go with the shields.