Anyone ever used a nuby sippy cup?

My husband and I bought our son a sippy cup last night at walmart. it's lime green with handles. Its a No Spill Cup with soft silicone spout. Its 10z cup. Any other moms out there ever let there child transition to this kind of cup? Hes going to be 6 months old soon and I was only going to let him maybe take few sips here and there..to just try the cup out, but we will still be using a bottle in the meantime. So when we fully transition to a cup it wont be as hard. Or I just might save this cup for him until he's at least 7 months old or older. Any advice or opinions wanted. No rude answers