Without seeing you, it's unfair to say to drop one or the other. Nobody else on here knows how well you control these, how well your movement is, how they feel on your arm. we also don't know how they fit your pitch Arsenal - for example, if you throw a lot of cutters, throwing a slider isn't exactly very reasonable.
So YOU need to take this poll and decide.
Do either/both of them fit your Arsenal? (Velo difference)
Does either pitch hurt your arm?
How well can you throw them? (Control, movement)
At what rate do you improve?
How about your mentality? If you can't execute the pitches, don't throw them.