I first read the book a few years ago and it has remained a firm favourite. The docudrama was enjoyable, concentrating on a few themes from the book, especially the constant pressure of fighting day after day for months.
The book has a great deal more than this Jeff, so the film won't spoil it for you. Highly recommended.
Another book I enjoyed recently is Brotherhood of the Skies by David Ince which redresses the fighter -versus-fighter emphasis of the early WW2 books. Ince flew Typhoons from late '43/early '44 to the war's end and is very interesting on the 2nd Tactical Air Force's close-support role from Overlord to VE day. Not anywhere as well-written as First Light - he could use a better sub-editor - but I mention it particularly because Wellum finished the war as a production test pilot on Typhoons.
And there's some pointed talk of Horton flying wings which some recent broadcasters could have read to their advantage...