Well, he did say 3 or 4. And that is only 4...
The scrum will be fun. Personally I think the O's should have a slight edge, as while Botha and Jones are both top class tightheads, I'm inclined to think that James is a better player and Du Preez. Also, if i were given the choice between being able to call on Stephen Archer or Ryan Bevington, it's not a toughie.
The respective second rows are quite evenly matched as well. Evans and Wyn-Jones are both proven internationals class, and Evans is in top form this season. The Munster pairing also have their fair share of caps and you'd imagine that O'Driscoll will be giving it absolutely everything in what may be his last game. They're helped out by having Ryan in the back row, who is obviously a very good operator as well.
In the back row I'd fancy Tipuric to be too good for O'Donnell, Jones to be about a match for Ryan (although I think the Munster man might shade it) and it to be pretty even in the 8 slot. It's the greater talent of O'Mahony against the greater experience of Bearman, which always makes for a fascinating contest. I reckon this is the one area of the pack where Munster could really be on top, but an awful lot of that comes down to how well Tipuric is dealt with.
Both sets of half backs are a bit meh. Munster probably have the better scrum half, Ospreys the better out half. Munster do have the luxury of bringing ROG on at some point though. Ospreys probably have better centres (I've never been a fan of Mafi and Earls' best spot is on the wing) while Munster might shade it in the back three (I reckon they'd have two players in a combined team, but Shane is obviously a class above anyone else).
Could go either way really. Ospreys probably look the slightly stronger unit on paper, but one thing you learn about Munster over the years is that they just wont **** off and lose when they should. Should be a good game.