I'd disagree with both of these sets of odds, although of course it's still speculation this far out. I think the GOP's greatest risk is at the governor level. They have 23 incumbent seats to defend, and a ton of incumbent governors of both parties are not doing well in the polls. Voters are apparently blaming them, not the President, Senate and Congress, for their problems right now. Will this hurt the House or Senate races? Sure, it could. Or close governor races may improve turnout in various races, helping either party.
Having said all that, I think in Nov the GOP will still end up with governors of the nation's four largest states, even if it may no longer have a majority.
OK, you can out yourself now. What are you odds?