I have run this race for the past four years and it keeps getting better. The fast, flat course is good for a PB and it's largely scenic (about as good as you'll get in London, at any rate). Great marshalling and organisation, decent goodies (I particularly liked the bath salts this year - very useful). I'm not such a big fan of plastic cups - very hard to drink from. That's less of an issue in a February race when it's unlikely to be hot, but for warmer and/or longer races, it could be an issue.