Also, I won't argue that 4♥ is a really messy bid, but I think it will be the only time in this auction where I can cuebid without the trumps being ambiguous. If I bid 4♣ and partner bids 4♦ or 4♥, I'm not confident what suit partner is supporting. I'm sure kenrexford has this all sorted out, but short of that I'd like to have one unambiguous slam auction if we have a ♠ fit. If you bid 4♣ and partner bids 4♠, you'll wish you had done more, though I concede slam rates to be not great after that auction. Edit: And I know this is a problem with the "game before slam" principle, which in itself might make 4♣ clearly better, though you won't get to 5♦ if it's right by bidding 4♣.