I applied through Tokyo marathon's own charity system which worked out considerably cheaper than going through a sports tour company. 

Expo had plenty of clothing to chose from and was a noisy, lively affair. 

The race was well organised and involved several security checks, including every runner wearing a secure wrist band which was scanned before being allowed to enter the race start area. 

The course was fairly uninspiring - lots of boring concrete buildings and only a couple of interesting points (a large shrine, Tokyo tower and Ginza Street glitzy buildings). Saying that, I found the race really enjoyable. The crowd support was brilliant and the food stations were the best I've experienced on a race! Cakes, tomatoes, biscuits, bread, jellies, plus the usual water and isotonic drinks. 

Finisher t-shirt was a little nice but I was disappointed it was unisex (shapeless!) and mine was huge and I wasn't allowed to swap it. Medal is great and the commemorative bath towel was nice. 

As a charity entrant I was looked after post-race, which was very welcome.