I went without one too initially, but the rail covers are more comfortable, and there are many styles to chose from. I just happened to have the ones shown, but a quick search shows many out there. ( These two just happen to be the right size to fit perfectly without cutting )
I agree Troy, I just happened to have those already but will be looking for smooth ones next.
Good catch on the stock cheek piece Troy, but I just measured and the stock piece without the top cover is still about 25% higher than the rail covers, and every little bit helps.