I use the grid a lot, pre and post workout but also use the other rollers (footballer and quadballer) for more pinpointed stretching/massaging. When I was at Interbike I talked to the TP people and told them about issues I was having with forefoot pain. They recommended this exercise
with the footballer
to stretch the soleus and it's helped a lot. However I also have very poor dorsiflexion. As for the inner thigh somebody mentioned...I saw a picture where they were using the quadballer for that (I can't find it now) although I don't personally do that exercise and will now give it a try, I hit virtually every other muscle in the legs, glutes, and lower back.