Some of the differences, as I see them:
Bond is more vulnerable. He gets hurt a lot. He is afraid, so much that throws uo out of fear a couple of times. He is occasional delusional, and has a more strained relation to the service.
Bond's humour is closer to Daniel Craig's Bond than to the other Bonds. That is to say, virtually non-existing.
There is less action in the books. When I reread some of the novels a while ago, that surprised me. Not to say that there aren't any at all.
The books have wonderful descriptions of persons and places. The opening of From Russia With Love is in my view some of the best.
I would also recommend Moonraker and From Russia With Love, and also Dr. No. If you want to read James Bond books written by other than Flemming I recommend the two my Anthony Horowhitch (I hope the rumours of a third is true!)