They are both great cigars, but while I typically prefer earthy over peppery, I find that the T52 is my favorite of the two.
As for sizes, I enjoy both the toro and the robusto. Difficult call, but I'd probably decide based on how much time I have to smoke.
For a few bucks less, the Undercrown is a great smoke for the price. Like the T52, it is made from stalk-cut tobacco, however its leaves are from a different layer of the plant than the T52, which receives the very best.
Drew Estate has a real winner with these 3. They've very quickly moved up in my rotation.