- Best-designed weighted straw I've seen: It has a rounded bottom and the weight is disc-shaped, so the weighted straw moves super smoothly around the cup and my daughter has no problem drinking at any angle.
- Fairly leak resistant (when using room temperature liquids), meaning if your kid tips it upside down or throws it across the room while using it, at most a drop or two will come out (whatever was already at the top of the straw). But I would not trust it beyond that (see below)
However, this cup also definitely has some negatives:
- The click lock feature isn't super helpful, and makes it unnecessarily hard IMO to open/close the cup (if you overtwist it, it's very difficult to get off)
- The flip-top lid is not securely attached and falls off frequently. As a result, this cup is definitely not one you'd trust upside down in your diaper bag
- In addition, if you use this cup with cold/refrigerated liquids, the temperature differential causes the liquid to get sucked up through the straw and spill out of the top. Like, all over the place! (This issue will occur with any sippy that does not have a vent) So, I only use it for room temperature liquids, like water or freshly pumped breast milk. If you want a cup that can be taken in and out of the fridge, this is not a good choice
- Handles are not removable (not a huge deal though, since I figure that once my daughter no longer outgrows the handles, she'll also have outgrown the need for a weighted straw)
- Hard to clean (due to the weight at the bottom of the straw). For this reason I usually only use this cup for water (or if I need to use it for milk in a pinch, I make sure to wash it out immediately & thoroughly afterward)
However, we live with these negatives and still reach for this cup first (during this training phase when my daughter is still regularly trying to drink with the cup upside down) because the weighted straw feature is so much better designed than other cups.
For those also considering the ZoLi BOT Straw Sippy Cup - Orange 6 oz : I used that one for several years with my son. Same idea in general, but the weighted straw does not work as well; the cup has to be turned almost entirely upside down in order for the weight to fall to the top of the cup. However, the Zoli also has some advantages. It's much easier to get the lid on/off, and the flip-top lid is much more securely attached as compared to the Munchkin.)
I will continue using this cup as a trainer until my daughter learns that she can keep her straw cups upright while drinking, then I will get rid of it and transition her to a straw cup that has a vent, can be tossed around in my diaper bag without leaking, is easier to clean, and is probably also not made of plastic. For the record, my favorite sippy cup for older babies / toddlers / preschoolers (who don't need handles or a weighted straw) is the THERMOS FOOGO Vacuum Insulated Stainless Steel 10-Ounce Straw Bottle, Blue/Yellow .
I'm posting a video highlighting the key features of the Munchkin (including the weighted straw, click lock feature, and flip top lid) and also comparing the Zoli. Also a picture of my daughter drinking of out of this thing while holding it tipped up & backwards with no problems. Hope you find them useful!