I tried another hourglass that was smaller but the sand kept getting stuck in the glass, so in order to get it moving again I would have to shake it, which is not what you want in a sand timer. In this model, the sand does not get stuck in the glass, so you get a clean run of the sand filtering down through the glass, and thus it actually keeps the time and actually works... Yay!

This is a good hour glass. Sometimes the sand gets stuck on the glass but you can shake it off by tapping it. Mine is off by an extra minute but that's not an issue for me. When the package arrived it was in perfect quality and the hourglass itself was packaged excellently. I recommend this hourglass.

Very good timer overall.... but...

My timer is about 25 minutes. Which is still fine for my purposes, I'm using it for pomodoro and 25 minutes is actually the traditional pomodoro duration.

One other imperfection, a tiny bit of sand clings to the glass as the timer runs out. It actually makes some cool looking patterns and knocking the glass will cause it all to fall down and finish draining in seconds. But it doesn't look perfectly clean to have some sand stuck up on the edges of the glass. Easy to knock off, but the sand won't all drain entirely by itself.

I got the white sand version and it looks very classy, the sand has a slight sparkle to it. I have noticed some extremely tiny black flecks in the white, but they are hardly visible and don't bother me. The glass is clear and sturdy, but it can get fingerprints on it from repeated use. I plan to build myself a wood frame for it, so I can keep the glass perfectly clean.

Pro's:
Hourglass arrived well packaged; an important feature for glass.
Accuracy is very good, running at 30 minutes, 14 seconds -- Close enough for my purposes.
It's attractive and well made. Glass does not appear to be fragile, with the thinnest spots being on the flat ends.
It's quite stable on both ends and has scooted across my desk rather than tipped when gently bumped.
You can stop the timer by placing it on its side. It will rock, but not roll around and doesn't need to be chocked.
Sand appears to be fairly consistent in size and low in moisture content. Very little residue remains in the upper chamber when the sand runs out.
The price is excellent at $9.99 with prime shipping.

Uses:
Whatever you desire of course. I use mine in the office for two different purposes.
It's terrific for reminding me to stop and stretch every half hour or so when focused on computer work yet it doesn't break my concentration with an audible alarm.
I try to conclude most office meetings within 30 minutes or so. Many people ask about the hourglass then tend to self-regulate as the sand flows. This provides a gentle way to bring meetings to a close, especially for people with disabilities or those who illustrate with stories. Some people will flip the hourglass themselves as a meeting begins which helps us both to be more respectful of each other's time.
I plan to order more to help me keep track of the passing of time as I focus on home projects.

Cons:
None really. The attached tag was crunched and folded making it less suitable for gift giving. But at this price I'm not really concerned.

I'm a huge procrastinator, and always attracted by other things while I'm studying/working. I want to find some creative way to bring my focus back and it works perfectly for me. It gives me 30 mins of good focus-- every time I looks to the side I see it still going and I kinda force myself to continue working. it's like a reflex training thing, and it works well.

I was a bit worried because lots of comments says it's fragile. I've been flipping it every 30mins from 10 am to 8 pm for three weeks and there's not a single scratch. The sand is fluent, time is accurate, and the glass is strong. Good stuff.