Clock is ok but works for 3 min then stops
The clock is OK but works for about 3 min then stops. It is good for education to teach your child how a wind up clocks work. The toy is fun to build but a little frustrating also. I sent the clock because it didn't work right.

Depends on what you want it for
I bought this clock for my 3 year old who is currently obsessed with clocks. I tried to find a kids clock that would show how a clock RUNS, not how to teach a kid to tell time, which are what most toy, non-running clocks are. The only clocks with visible gears I found were executive-type, expensive and very much not for kids. So while I didn't want to put one together myself, and was hoping to find one that would stand up better to a 3 year old, this clock is pretty much just what I was looking for.
Yes, the directions are terrible, even though I understand it is supposed to be a puzzle. The pictures given are small and hard to read. I got the clock mostly together myself but it would not run. My husband ended up taking a crack at it and got it running, but he's "The Fonz", and can put anything together. Between the two of us it took about an hour. I can't imagine a 6 year old putting one together. However, it would be a great project for an 8-plus kid and parent - who is good at this sort of thing - to do together.
So my husband got it running and even tweaked it so that the bell will ring at each quarter hour - don't ask me how, but now if I want it to do it again I'll have to figure out how because it does only run for about an hour or so at a time. It IS fragile. Our daughter wants to pick it up and play with it but it definitely is "just to look at" - which she LOVES. It shows the gears moving and the pendulum swinging and the bell ringing and makes a very toddler-satisfying ticking sound and she can wind it up. But then unfortunately she can't touch it or else it will stop running. It is also made of cheap plastic.
For the price and for what it is, I think it's fine. It WILL show the inner workings of a clock. I think it would be great fun for an older kid who likes to put things together (it's more a "Process" rather than "Product" thing in that case) - and then fuss over it to get it to work. It's not rugged by any means but as long as you don't have any other expectations for it other than to show how a clock is put together and runs with gears it's probably about as good as it can be.

Easy to assemble but just doesn't work
This was a gift for my six year old who is very good at following instructions and working with his hands. We sat together and navigated the terrible assembly drawing. The basic drawing problem is that the step by step drawings are too small and the persepective chosen for their rendering has two pins that overlap. If you could figure out the drawing, assembly was pretty easy. The color coded parts helped a lot.

The operational problem with this item is the regulator (pendulum) mechanism. The fork and escape wheel are not made with sufficiently high precision for this item to work. When you first start the pendulum and it has high amplitude, these items engage and disengage properly. In 10-20 seconds, the fork and escape wheel actually start missing each other and the escape wheel goes several ticks per swing and then many as they miss each other and then the pendulum and the escape wheel stop moving together and the clock stops. There really isn't anything you can do about this problem. These parts have to fit perfectly and they don't.

Given the problems with the toy, I could not possibly recommend it.

Neat idea, a little frustrating to build but persistance will pay off!
My 6 year old son bought this. He worked for weeks to make enough money to get it, he loves clocks & the inner workings of them. To save us from him tearing apart clocks & watches, we agreed to order this for him. When I saw this out of the box, I really thought it looked quite junky so I was prepared for a failure from the start. My 9 year old daughter & I helped my son build it the first time but we could not get it to work. Then his sister took it apart & built it again, still it wasn't right & I was ready to send it back. Then, my son tried one more time & he got it working perfectly. The gear pieces have to be 'engaged' & there is some room for error but if you check & double check that everything turns before you seal it up, then you have won half the battle. Once you get it set & working, don't mess with it or it may cause you problems. Ours ran for the whole day yesterday, I was tiring of the constant tic tocking BUT my son has already learned so much about something that doesn't use batteries & shows the beautiful workings of mechanics. The process of building it & rebuilding it probably taught him more than if he would have built it right the first time.

I would not recommend this for a child who isn't careful with their toys, I could see the parts disappearing or being broken quite easily. Aside from that, it is an excellent learning tool!!

Perfectly imperfect
Wow is this a great object. 'Toy' is the wrong description, however. I bought this for my six year old son and we assembled it together. The instructions are not great. They are also not terrible. We tried to use the instructions as little as possible in any case, and the picture of the completed clock on the box is enough to deduce it all if you are mechanically minded and have the time to think through the elements you can't see very well (though part-color is not perfectly reliable from the picture). Both of us learned a lot in making this. That surprised me a bit. I'm college science professor. I've opened many clocks over the years. I did not, however, realize that a clock could be this simple, or this tolerant of imprecision (these parts are cheaply molded plastic). Half way through making this "clock" I became convinced that it was not as the box suggested. I thought it was not a clock, but instead a clock-like toy that would show how the hands could move at different rates, all in a highly sped-up form. I thought it wouldn't keep proper time. And I concluded that was ok. It was still fun to build and was well worth the price, even if the box was misleading. But then the last few steps (the hardest ones to deduce) rendered the entire thing functional. I was wrong! It keeps time. You have to adjust the pendulum to get it to do so precisely, just as someone must in any real pendulum clock. My only complaint is that this clock removes all the black-box elements from a clock except one. The spring that stores the energy that drives the clock is not possible to see. So there is still a black box, and for no good reason. The spring gear apparatus could be transparent so you could see every moving element. But at the price, I can't complain. It's tremendously educational, enough that I'm thinking of buying a stack and putting my students through he exercise of discovering how comprehensible things can remain un-comprehended in a consumer culture where a clock is typically something you buy, use, then throw away.