The 600 "should" win, but with all of these posts that ask whos sled will be this or that, it all comes down to who has the better set up, driver, distance, and conditions. Way to may variables to pick a favorite or for me to put money down on any one sled. I do know for a fact thought that both sleds have a ton of potential. A buddy of mine has a '99 600 twin running almost the same speed as my 600 trip/trip in 1000', but he won't fess up to what all he has done to it.
All he has to say is that the rule book just say that it has to "appear stock", which it does....haha
Anyway, getting back to the topic, the 600 should have the upper hand in a long run.