The multitronic's are a LOT better after 2007 (when they swapped to the 7-plate clutch, instead of the old 6 plate).... so that covers all C7's....but definitely don't do near it if you drive with any level of enthusiasm*.... or you're even vaguely considering any sort of remap - even a conservative "economy" map as that just releases a lump of low-rev torque that those boxes don't like.
*My opposite neighbour had a 62plate 204PS from new: no admittedly he used to thrash the hell out of his car, despite it only being a 204PS, but he went through 3 gearboxes in the first and then two more replacement cars in about 9 months... ended up packing it in and buying an S5 Sportback... which he pointed out that he'd done more miles in as a courtesy car than the car that he'd actually bought...
Unless you desperately want an auto and can't afford the entry-level quattro's (which are definitely NOT multitronic), I'd seriously consider holding out for a manual, but it sounds like you'd probably prefer the manual anyway.
On the flip-side: is tax / fuel economy a significant concern? If you need an auto - seriously look at the entry level 3.0TDI quattro's - they're still very reasonable in terms of cost to run and I think the mid-riange TDI probably returns equivalent real world MPG to the lower end model as the turbo allows it to hold higher gears a lot longer... if gearbox life is a major worry, then get a mid-range TDI with the EIGHT speed (ZF) box and skip straight past the STronic too... the ZF's have a pretty good reputation and are about as bulletproof as auto's get.
