I'm certainly not an expert on my cuts of meat but speaking from my experience cooking meat (at home) either cut is about method and time. Whenever I have a cheap cut of meat (sometimes I prefer them) I season, sear and roast and roast and roast. I just made a combo of veal and pork shoulder last night for dinner, their fabulous slow roasted! Slow, low temp. cooking can turn any piece of meat into a delight.
First of all how are you preparing your top round?
Top round should be served MR cold or hot and sliced very thin.
However the bottom round "from the leg"requiers braising (like a pot roast)to tenderize the muscle.One easy way to understand how to cook certian cuts of meat are to understand what part of the steer it comes from.The more the muscle works the tougher the cut,IE Eye round,shank,knucke face,shoulder clod ETC,Tender cuts like Tenderlion,109s,1 by 1s ect are muscles that don't work hard,thus develope a fine marble and need quick cooking.