S5 with Emobile or oneplus one SIM only?

Out of contract, use s3 currently with Emobile on friends & family plan, unlimited everything. Great plan as it's €34.50 so don't really want to go to a more expensive plan. Got quoted stupid money to upgrade on this plan.

Been looking online and best bill plan seems to be with Emobile, unlimited +data (4G). I know it's 5gb data but that's enough for me. €24 first 6 months, €39 after that for 18 months. S5 is €99. Works out at €945 in total over 24 months.

Alternative is to try get the oneplus one, seems a top phone. Best Sim plan with 4G is again with Emobile, €24 a month. Phone is about €360 so total over 24 months is €936. Not much of a difference.

Any opinions?