I use paper cups to take on my drive to work and then use throughout the day. I've given up on the commuter cups, because they always ended up being left at work so I couldn't use them the next day. We have an employee coffee machine at work, but in a different building, so when I refill, I refill big! This cup holds two servings of that machine's coffee. (Mostly decaf, in case people are wondering, LOL).I'd used this company's other (smooth sides) cups previously and was reasonably satisfied, although I'd had a few "duds" out of three orders where the lid wouldn't fit. I was intrigued when I saw these cups; I was a little hesitant to buy them because they cost more per cup than the others, but gave them a shot and I'm glad I did.The previous ones included sleeves which got loose and invariably slid off at inopportune times, usually getting left behind in the car's cup holder. I love that these cups don't need sleeves, and I can still pick up a fresh cup of coffee and it's not too hot to handle. The lids fit well, and go on easier than the other version. The whole cup just feels sturdier. These are so sturdy that, should I remember to take one home, I'm sure I could use it again the next day. These cups have survived the microwave with no problem. And for those who wonder, yes a straw fits through the hold; that is how I drink coffee on my way to work.Lastly, I have to compliment the company on their great customer service. They are very quick to reply to email and helped me out with a problem that wasn't their fault. Try these; you won't regret it.UPDATE after a month of use - one small irritant I've found is that the cups, which come stacked in side of each other, can be difficult to separate. I've had a few that I gave up on because I was in a hurry, and came back to later and managed to dislodge them. The other is a somewhat larger irritant, is that the bottom part sometimes leaks. Not the whole cup, and actually not even the very bottom, but the white "band" around the bottom edge, below the "corrugated" portion. I had one start to leak before I even made it out to my car. I thought at first it was because the cup is sitting in the drip tray of my coffee maker and perhaps it got wet, so I'm extra careful to clear that tray out. However, I never had that problem with my other cups (non-corrugated) from this company. It's only happened a few times, but should it become a more regular event, I'll have to go back to the old style. On the plus side, the lids on these go on more easily than the other model, and seem to stay on better.