I have therefore constructed my set without the stickers. Take a look at the images below and let us know whether you prefer this off-roader with its stickers applied or without them.
I would usually apply the stickers when constructing any LEGO set, although I think this model looks reasonable without them. Advertising decals certainly seem appropriate for a monster truck and I like the decorative skull design which covers the stickers. Nevertheless, plain flame yellowish orange and black panels are perfectly adequate in my opinion.
The only possible exceptions are the black 2x5 bodywork panels situated within each window. These seem incongruous beside the flame yellowish orange panels and applying the stickers alleviates that issue to some degree. However, they attract little attention, particularly when viewing this model from the side where they almost disappear against its dark interior!
Let us know how you voted in the comments.
Find further information about 42099 4x4 X-Treme Off-Roader in Huw's two-part review: