In my opinion (and depending on your application), naturally aspirated the LS7 is a better choice while the LSx would have an advantage if you were going forced induction. The LS7 has some other advantages, especially with respect to rotating mass which is nice as well. Equipping the dry sump in not that great an expense - Tyler at ATS has all the pieces available for that and the cost is really quiet reasonable; packaging is slightly more complex - you wind up with a lot going on under the hood.
I am biased here though, our LS7 is at Katech right now.
