Here is my personal opinion .
Full brush guards >look great on 3rd gens because of the more squared off front end . I don't care for the on 4th gen's because the headlight guards look like wings .
Westin Safari bar > look good on 4th Gens , nice size and tubing size kinda matches well with the size of the 4th gen.
Bull bar > Looks to bulky and reduces approach angles ( like both of the above do ) The tubes look to thick/bulky, out of proportion on a stock 4R . I think if the 4R is lifted it looks good and matched proportionately to the truck.
Any of the above does not look bad , just my personal thoughts. No offense to anyone at all who has any of these , just my personal taste , but we all have are own taste's which makes this so cool to see how everyone set's up their rigs and each others taste and we all have to respect that and get ideas and ways to blow more money on our own rigs