Hi Smacko,
while not a catamaran sailer, Sue and I have long term plans to go this way in the future. From what you have written it appears you have quite a budget from my browsing of the Oz brokerage sites. Being in South Oz you may well be protectd in the main ports but when you get out into that Southern Ocean I would want a Cat with some serious blue water credentials. My local barber ( a cat freak

) has just returned from delivering a Lagoon 38 from Vanauato to Bundaberg. We had a good chat over the delivery trip and he was very impressed with the boats handling but dissapointed in its finish for the money you spend. The biggest sea they encounted was 4 metre on a 3 metre swell and they turned around due to the nature and size of the sea and 30 knot plus winds. The boat would have gone on but as they were doing a delivery felt it prudent to turn back towards port which was less the half a day sail.
Personally I am a fan of the Seawinds, they are built in Australia for all Australian conditions. They hold their value and have proven themselves time and time again in all conditions. There is not a report I know of where they pitchpoled, or were rolled. The 1160 and 1200 on the second market fit your budget from what I can see ( I stand corrected if I am mistaken) Dont get me wrong I would have either of the boats you have mentioned but to me its horses for courses.
Regardless of what everyone else says, at the end of the day you and your family have to be satisifed that the boat you buy is the boat for you. Electronics etc are just extras and can be installed or updated at any time. Always remember while you are not buying new you are purchasing dated electronics, motors etc which may have to be relplaced. We looked at an older Robin Chamberlain 45 ft Cat which we just fell in love with. It needed some TLC but at the end of the day the electronics needed replacing as did both motors and what seemed a great buy was just a great money pit.
Not knowing your sailing background have you considered chartering one or either of the cats your looking at to determine which may better suite your needs. While not a cheap alternative it may save you tens of thousands of dollars in the long run.
Regards
Greg and Sue
Cheiftain 38 Lake Macquarie NSW Oz