You're going to want either a m/f or a m/xf. The extra fast action is great for finesse fishing, but the fast will give you a bit more versatile of a rod so it kind of depends on what else you have as well as how dedicated you're going to be to those techniques listed.
As far as sensitivity difference, they'll be pretty close. The Avid and Avid X are built on the same blanks, the Avid X is just a modernized version of their proven performer. The Avid X will be a little lighter due to the micro guides as well as the split grip and may balance a little better as well depending on your reel.