I started out with the 6m+ stage, where the handles are attached to the lid. These are absolutely spill-proof. (However you should note that liquid comes out when the nipple is squeezed/pinched.) I really loved this stage because my son could have it on the floor with him without making a mess and the handles were really easy for him to grip and use. We recently started on the 9m+ stage where the bottle is slender with no handle and the nipple is more of a straw. They work really well too, although my son still has trouble tipping them up and he's almost 11 months. (So you might want to stick with the previous stage for awhile.) These are dish-washer safe which is great, however mine always end up tipped up so I end up washing them by hand anyway. Bpa-free and a good price for 2. (I paid 7.99). I'll keep sticking with these. Not to mention my son likes them so much he won't drink from any other sippee cups. UPDATE- Eventually the 6m+ and 9m+ styles started leaking. It might have been my fault for the way I was cleaning them (I used a nipple brush inside the nipple) but there was gunk building up and I couldn't see any other way to really get that gunk off. However, we're on to the 24m+ which is the kind pictured and these are totally wonderful. I don't think we'll have the same problem. Also, we started on the 24m+ after the 9m+ and that's worked really well so you might try the same and save some money by not buying the cups in between. UPDATE 4/2012- I've had to downgrade my rating of these cups because no matter what stage we've used after a few months they start leaking (the 24m+ pictured included). At first they are leakproof but after awhile of washing and using leaks start happening more and more frequently. I had wanted to use these cups with baby #2, but since these didn't last we're looking into other brands to see if they will hold up better.

momyofbug

Mishawaka, IN

These cups are outstanding, I have to say I have gone through a lot of "spill proof cups" and these for me are great. Not to many pieces, very easy to put together, I love these cups. The spill proof pieces are just 2 pieces you have to put together and then put it on the lid.. They don't leak, you don't have to put the lids on super tight like some other cups. I don't know what else to say just that I love these cups...

heathermbain

Roseville, MI

The early stage Tommee Tippee cups are great.  They have a unique design that is not over stimulating or overly "babyish."  The cups are truly leak proof so long as you properly install the valve system.  The early stage cups are also nice because the handles are attached to the lid so there are no alignment issues like with other cups.  These cups are easy to clean and do not require the purchase of specialized cleaning equipment. I began having issues with the Tommee Tippee once my son was moved up to the older stages.  The cups that contain the spout similar to an adult water bottle were the beginning.  The cups were great until they were dropped.  The height dropped would only be from the stroller to the floor or the highchair to the floor.  Once the cup was dropped the seal would become undone and the cup would begin leaking where the top and bottom meet.  The lid would slighly deform and you can never get a good seal again.  The straw version is horrible.  If you remove the straw from the lid, it is VERY difficult to relace it.  We had the same issues with the dropping and seal leakage. If you do not install the valve system properly, you will not get any flow through the straw and for the life of me, I could not figure out how the valve was not installing properly. 

Gegesbeachhouse

Winnabow, NC

I picked up the Tommee Tippee Explora Truly Spill Proof Drinking Cups when I was out looking for new sippy cups for our daughter.  I liked the bright colors and designs on them and tossed them in my cart.  I got the pink and purple 2-pack that's in the picture. These BPA-free cups hold 9 ounces.  The bottoms are insulated, so drinks stay cold longer.  Though this does make it a pretty large cup so they take up a lot of space and can be hard for little hands to hold.  They're comprised of the cup itself, the lid, and a two-peice valve.  The valve has a soft and a hard component that fit together and then snap into the lid, creating an on-demand drinking system.  They aren't bad as far as leaks go.  I haven't had any problems when they tip.  Though if the spout gets pushed against a soft surface such as a couch or bed, it will wick the liquid out and make a mess.  If they take a hard shock or fall onto a hard surface, the valve can come displaced, so these may not be the best if you have a thrower. The packaging recommends these cups for 24 months and older.  My daughter had trouble drinking from them until she was about 18 months or so, so I'd say that's pretty accurate.  Until that point, she had trouble figuring out where to drink from as they don't have a traditional long spout like most sippy cups and she seemed to have trouble sucking hard enough to get the liquid inside to flow.  Now that she's a little older, these cups are great.

GMRsMom

Oakland Gardens, NY