I walked OD in September 2002. I had previously walked the Pennine Way and Southern Upland Way. I have since walked WHW and Great Glen Way, all alone.
Coming from Brisbane, any walking in Britain is wonderful, however I have to agree that OD was the least enjoyable of all. Admittedly, the weather wasn't very kind to me and I also fell and fractured a bone in my hand just north of Knighton (and on my 58th birthday!). I soldiered on, but crossing stiles became a real challenge!
The southern section is the better half. I finished in Prestatyn on a week day in September and it was relatively quiet, so didn't experience any problems. It is an anticlimax though.
Pennine Way was my first LDP and to me still the best, although I am doing The Ridgeway and Coast to Coast next June, so my opinion might change!
ANY LDP is a challenge and an adventure, but gives one a great sense of pride and great satisfaction when completed.