So I purchased some GC today and bought a 50% RP/XP item from the store. I was surprised to see the awesome little notifiers after a round ends of how much "bonus" XP and RP you got. Check the bottom of the scoreboard in the following pics for reference:
There's also a section in the Match Results where it tallies Bonus XP and RP before Grand Totaling it:
All-in-all I like the UI cues to point out how much extra I'm earning by using a Boost!