Peter Bacon and Tim Dickeson have done a great job in evoking personal recollections of Cheltenham Jazz Festival. Check out their blogs on http://thejazzbreakfast.wordpress.com/ and http://editionontour.blogspot.com/. Uncostrained by space limits that the national and specialist press will have and therefore able to interpret the subtleties of the music.
There is also a Jazz on 3 broadcast from the festival but again limited to a single intense programme with highlights
Cheltenham is not a cheap event to go to if you're not local. The price of getting there, the price of accommodation and the admission fees.
By contrast, I look at how things are covered abroad. As a member of a group called Radio Jazz Research in Germany, I have regular contact with a number of journalists and radio producers, especially from the WDR area. WDR alone records 6 (!) festivals, just in their own region of North Rhein Westphalia. It includes festivals such as Muenster and Moers.
From Muenster alone they will broadcast 6-8 hours of music. (Having been there, I can confirm that some of it, with the likes of Rudresh Mahanthappa, Rita Marcotulli and a young marvel pianist Pablo Held, was fantastic. Never less than worth hearing.)
Meanwhile a few newspapers will probably review the festival with maybe 1000 words maximum. How can 90 minutes of music and 600 words cover a festival with Dave Douglas, Dave Liebman, Jack de Johnette, Hugh Masekela and and and?
The BBC is still providing adequate coverage of a few festivals. They record the totality of Huddersfield Contemporary Music Festival as well as some of the concerts from London. Cheltenham or Bath are equally creative.
No wonder jazz continually gets short shrift.