If you like trekking through mountain scenery, then the Annapurna Circuit is an absolute gem. It's a well-known and relatively safe walk, and although it's very popular with foreign walkers, this doesn't detract one little bit from the incredible scenery. It's one of the world's great treks, no doubt about it.
I tackled the Annapurna Circuit late in my walking career, and I assumed that it would be a piece of cake. In the event it took me a lot longer than I anticipated. My leisurely route covered the 200km trek in 15 walking days, with an additional day on the bus and five very welcome rest days; this works out at less than 13.5km per walking day, which is pretty slow compared to a lot of walks I've done.
However the Annapurna Circuit was my first walk at altitude, and however fit you are, it makes life incredibly tough. The lack of oxygen at these heights means you get out of breath after just a few steps, and the moment you break through 3000m above sea level, the potentially serious threat of Acute Mountain Sickness hangs over everyone. Even though the vast majority of people get through the trek with little more than a mild headache, it can really spoil the experience for some; people have died from AMS on the Annapurna Circuit, just because they ignored the signs of AMS, so it really shouldn't be taken lightly.
But the statistics show that the Annapurna Circuit is a popular trek, and it's no wonder when you consider what it has to offer. Once you leave the bus at Besisahar you won't come across motor transport until the very end, and the cool mountain air is so fresh you can almost taste the goodness. Sure, the impact of thousands of trekkers isn't trivial and there are problems with litter, but given the numbers the whole thing is managed pretty well. Indeed, before I walked this trek I was told its nickname was the Coca-Cola Circuit, because of the infiltration of Western luxuries along with the crowds of Western tourists; but while it's true that you can buy Coke all the way along the trail, it takes a lot more than a drinks manufacturer to ruin the Himalayas. Whatever happens to the Annapurna Trek, those mountain views will always be timeless.
I'm full of admiration for people who've managed to do the whole Annapurna Circuit; it's no mean feat. But whatever the challenges, it's worth it, because the mountain views are second to none, the Nepalese are delightful people, and the atmosphere is unique. If you have the time and the inclination, this really is a special walk.