The finish is slightly different the one shown on your link Crash Hamster. They have moved it from where it was last year. It won't make a huge difference but I like knowing these things in advance all the same.
The course is mostly flat with a few minor inclines and one hill (the descent can just as hard as the ascent) to keep things interesting. The half marathon is one lap, the marathon is two.
The first lap includes a loop around Stratford-upon-Avon town centre, the second includes a longer stretch along the Greenway (disused) railway line. The Greenway can be a bit soul-destroying if you don't have much in the tank or you don't have many runners with you as there is hardly any crowd support along that section.
It is a nice enough route without being spectacular. There are pactches of support although these are few and far between. The second lap does feel lonely as the majority of entrants do the half and, as I said, the Greenway is not the most exciting place to run. Once you are over Rumer Hill you don't have any undulations to contend with, which is nice.
The loop around town can be congested but at that stage of a marathon there's never much room for manoeuvre at any venue. The route along the river towards in the final half a mile is very pleasant and the finish is opposite the Royal Shakespeare Theatre, usually attracts a fair crowd.
It is genuinely a runner-friendly course and although my comments are maybe a tad downbeat on review, I did actually enjoy the race.
The course map is on the website, although I know maps don't often help very much!