This beats the pants off any other construction set on the market, including Knex and especially any form of Lego. My 12-year old son loves it, and can spend hours of non-computer time on it, which has to be a significant improvement in quality of life! My only real disappointments are firstly that you can't get anything like the size kits that were available when I was a kid - the number 10 was evey budding engineer's dream - and secondly, closely related, you can't buy the conversion/expansion kits that you could then. This isn't the same as just buying a second set, it gave you precisely the parts that you needed to convert your existing set into the next larger set, which was not just quantity but also more complex components. Having said that, I only ever got to a number 7 kit back then, and I would say that this particular set probably matches that.
Unlike even the most technical of the lego sets, this really emulates engineering in the real world. I am a Chartered Engineer, largely due to having had Mecanno as a kid. My instinctive understanding of how engineering structures and machines work came from the lessons I learnt producing models with this stuff. I have also checked with numerous other colleagues of a similar age-group and a little younger (I'm 56)who have particularly strong, inherent engineering skills and find that, almost without exception, they had Meccano as a kid. Lego does not do this - it achieves instant gratification from being able to emulate real world items in a non-real world manner - in other words it just cheats. Perhaps there's a link to more modern attitudes in this?
Contrary to what one other reviewer said, the kit is no worse than it was in those days - as then, the models built require patience, persistence, and careful adjustment in order to work correctly. The precise positioning of components, and suitable tightening of fixings can be quite crucial to successful operation. This mirrors the real world, and was no different with the meccano I had as a kid. Indeed, some of the modern developments in the kit (more flexible plates, inclusion of modern technology, etc.) have improved it, or at least kept it up to date with the real world. Without a doubt, construction can sometimes become frustrating, particularly when components have to be fixed in positions of very limited access - if we could somehow combine the skilled dexterity of an adult with the small fingers of a child, we would have the magic formula for success - however, persistence and patience is more than rewarded by the sense of achievement on completion.
The more or less absence of electronics from this or any other kit is possibly one criticism, however, I can see that this would be difficult to fit with the Meccano concept - the black box that has no visible sign of how it achieves what it does is in direct conflict with the transparence of engineering principles shown by Meccano in its original and current forms, but it would be a more accurate mirror of current engineering.
Highly recommended.