Interesting situation. They both play nearly the same amount of minutes but the breakdown is a bit different.
Filppula skates with Datsyuk and Bertuzzi predominantly at even strength but Bertuzzi and Cleary predominantly on the power play.
Boyes skates with Grabner and Nielsen predominantly at even strength but with Tavares, Nielsen and Moulson predominantly on the power play.
I'd say stick with Filppula because I trust him a bit more but it's kind of a coin flip. It might come down to what you need more: plus/minus or PPP because that's where there's a difference between the two.