This was my first Run Through event and I know they're very popular with some of the @ukrunchat runners, and now I know why.

Pros

• Easy registration process and reasonable price
• You can choose whether you run 5k or 10k on the day (I guess it makes for quite an expensive 5k but the flexibility is good)
• Marshalls en route to the start to point you in the right direction
• Bag drop, loos and warm up provided
• Very easy number collection process (all numbers collected on the day - you get an email with a link to check your number in advance to make this even easier)
• Fabulous medal, themed to the venue (this one has runners on it because it's the Olympic Park race).... so....
• For those who fancy it, you can enter the whole race series (I assume at a slightly discounted price) and get the whole series of fab medals.  I believe the Wimbledon one has a womble on it. 
• Brilliant marshalls, who were encouraging and high fiving and generally rather fab.  In fact, probably the best marshalls I've come across for a "short" race (ie under a half marathon).
• Not a huge amount of runners so for those who are nervous of organised "races" or it's their first, it would be a good one.
• A heron! I saw a heron - 3 times because of 3 laps. By the third lap I thought he might have pottered off to do whatever herons do on a nice Wednesday evening, bored of having people thundering past him, but I think he was a secret running fan and was probably inwardly cheering us on in Heronese.
• Very pretty course around the wetlands area of the Olympic Park.
• One water station which seemed to have plenty of water, in sports cap bottles.  I didn't actually take any as I had my own drink so can't say how much they had left by lap three.
• Fab announcer at the finish line shouting out people's names.
• Free flapjack (yum!) or banana (bleurgh) at the end.  

Cons

• My usual minor whinge of not having a loo part way round the course.  A 5k is fine with no loo but a 10k can be pushing it for some people.  Saying that, on this particular route, it was 3 laps for the 10k and the portaloos at the start weren't very far off the course so if you were desperate you'd have scooted over there.
• It's a bit hilly.  But the good thing about a 3 lapper is that you know when the hills are coming on the next 2 laps and can prepare yourself.

So, as you can see, waaaay more pros than cons.  Which is why I signed up almost immediately for their Crystal Palace race.  I mean, who doesn't want a medal with a dinosaur on it!