That the President can't tell the Senate that it's in recess when it says it isn't is a no-brainer: I wouldn't be surprised to see 8 or even 9 votes to overturn the appointments on that ground.
The broader ground which has been argued is that, even when the Senate is in recess, the President can appoint someone only if the vacancy happened during that recess. The text of the Constitution literally says that, but every President since Andrew Jackson (really) has ignored that limitation. If the Court decides on that ground, then the whole Recess Appointment power becomes essentially a nullity. (And, as the Obama Administration has pointed out to the Court, that means that Dwight Eisenhower's appointment as the General of the Armies in WWII was illegal.)
I’d like to see the broader ruling, but I’ll be delighted with the narrow ruling. I really don’t trust the SCOTUS as I cannot fathom a Constitutional thread of their decisions, at least not one that is consistent. The only one who seems consistent is Thomas. I wish we had five more like him.
What’s your rulings scorecard? I mean how many times have you called it wrong? I hate to get my hopes up. ;-]