Our kid didn't get tilting the sippy cup, but he's an expert with the straw. We've been using the Playtex one with handles (like this: https://www.amazon.com/Playtex-First-Gripper-Trainer-Colors/dp/B004E2H3PA, but it's more like $5 at Target.) He gets frustrated with the no spill straws because it's so hard to get anything out unless you pinch the straw just write.
I love the stainless steel Thermos brand ones. They are easy for DS to use, plus they keep the liquid inside of them cold (or warm) all day.
We LOVE the Froogo brand. You'll gasp at the price but we've had the same two for years. I wanted something that wasn't plastic because I can always taste dishwasher soap in plastic. The tops are interchangable with the plastic clear bottom ones too which we used when the girls were smaller so we could more easily see how much milk they had to drink etc. But like I said, I could taste the soap after a short time.
Re: s/o Sippy Cups - straw cups
We used these for Gracie for almost a year until she started requiring a bigger cup. We loved them.
I like the Munchkin Flip straw cups. They're pretty leakproof and not too difficult to assemble.
We LOVE the Froogo brand. You'll gasp at the price but we've had the same two for years. I wanted something that wasn't plastic because I can always taste dishwasher soap in plastic. The tops are interchangable with the plastic clear bottom ones too which we used when the girls were smaller so we could more easily see how much milk they had to drink etc. But like I said, I could taste the soap after a short time.