It's a rather tough decision, but in the end I choose his
second half.
While the first half has some great books, the second half is more enjoyable.
First half contains Licence Renewed and For Special Services - two great novels, while Icebreaker, Nobody Lives Forever and Scorpius is merely good. Nothing that memorable. And not to forget, the horrible Licence To Kill. A really poorly written novelization.
The second half is instead much more fun.
Great stories like Win, Lose or Die, Death Is Forever, The Man From Barbarossa and Never Send Flowers. Especially the last mentioned is my all time favourite Gardner novel. The second half isn't perfect of course, let me just remind you of GoldenEye and Brokenclaw. To weak and hihgly uninteresting novels...