Quote from pumuecilsi tend not to need the tower spawn. i feel as if controllable units are more efficient.
so i vote no
Controllable units are good, but tower spawn gives you the opportunity to pressure hard and cave him in. You can attack, and when the tower spawn dies, kite out of there with your inevitable spearcher. Repeat a few times and you should be winning an attrition war with equal armies because you're using tower spawn.
Another thing you can do is have a battle which results in heavy losses for both sides with your tower spawn. When the tower spawn respawns, he has a lack of army to handle it and you can push hard.
Tower spawn is a great upgrade depending on situation - Classic OR DM.