The correct answer depends on what skill you'd like to sharpen first.
Making your own game will sharpen your design and production skills (and pretty much everything else).
Cloning will make you a better programmer, make you more familiar with tools, and give you a better look into why a good game is good.
Which one suits you? The easiest recommendation is to do both. Holy shit! Then, wait for it, you can switch between the two at your leisure
. The best way to clear boredom and creative blocks is to work on something else. Doing both at once may actually make both more enjoyable, _and_ you get the freedom. Yess.
Game development is just like the opposite of a woman. The more you do whatever you want with it, the more it loves you back.
The first game I ever did - 8 years ago (high school project) - was a clone. Never done that again, because now I'm a boss programmer, I study good games more quickly with my big-brain analytical skills, and working with my own shit is more liberating (also, my own ideas). The real value of cloning is for confidence building. What I really recommend is doing your own thing, then whenever you cry like a little baby, pop back to your clone, and be like, "I invented MegaMan, bitch." Just remember, I invented it before you.