at this point I really don't have enough information to say (due to my lack of research on the subject). I will say, however, that Rangers' pitching prospects scare me, but that may be guilt by association.

i hate ranger's pitching prospects and rockies. but between these two i prefer feliz which should tell you how little i think of aumont.
he's very raw. has only one pitch that can be graded as better then below avg. sure he will have a high ceiling, but that's many cause he's very tall and throws hard. but it's unlikely he'll capitalize on his ceiling unless he changes his delivery  because of the way he throws it's unlikely he'll be able to develop another pitch that is at least major league avg.

feliz at least, in my opinon, has a chance to be a starter.

He's further along and as bad as the Rangers are at developing pitchers, he probably won't be rushed. You can't say that about Aumont.