Out of the box? No contest. OEC is a lot better. OEC is gtg while NT is just a shell of a real trading app with function extensibility. You better demo, both. NT is from a different industry paradigm that had "free trading app" as a major cost advantage. Times have changed and NT is adjusting.
If you don't want to waste time building functionality, CQG's Qtrader with Excel RTD to analyze spreads, roll yield and historical volatility is a great package for $40. Researching right now if going CQG Qtrader will make them cut historical intraday to 3 months as opposed to 1 year 1 min data with NT Continuum.
CTS is also recommended but that is a different price range.