Lovely colours! It shows a plane approaching from the live (circuit) side. What the diagram doesn't make clear is what you do if you are approaching from the dead side. What you're supposed to do is go to the overhead at 2000 feet (or whatever), than do an extra 180 in the circuit direction to join the blue path in the pretty diagram. Then you do another 450 degrees of turning (following the path in the diagram) to get on final, by which time you've turned a total of 630 degrees and are probably dizzy.
Some people say, if you are approaching from the dead side, that you descend on approach and go straight to the crosswind point at circuit height. That may be OK at many airfields, but it's not an overhead join; it's a crosswind join.
I also don't like overhead joins, but I do whatever the airfield tells me to. The one advantage of OHJ is that it gives you more time to find the field and figure out where the runways are. For instance, finding Fenland at this time of year: one green field surrounded by a thousand other ones, all similar sizes...
I asked this at a CAA flight safety briefing and the CAA man said you go overhead then turn 180 dgrees.
Although, personally, I do a cross wind join....