Reply to IPAD vs Novation Zero SL MKII (ie. Hardware Controller)

Hey guys,
Im on the look out to start investing in some hardware controller to use with ableton both to assist in studio production as well as live performance (in time).

at the moment im siding towards getting a Novation Zero SL MKII + Launchpad (as opposed to an APC40, although im still mulling this one over)

the main purpose of getting the ZERO SL MKII would be to use for mixing and parameter control with AU's and ableton instruments/effects. In a live setting it would be for creative purposes...filter business, bring tracks in and out etc.

however, it seems the IPAD with assistance from software like TouchOSC or perhaps Lemur may be able to achieve a lot of the same tasks as the Zero SL MKII. in addition, to buy either second hand they would be fairly close in price (oddly enough...)

I have no experience using either so im curious which option you guys might believe is generally better.
Im mostly concerned about fader sensitivity in both cases...can i make subtle tweaks in the mixer?