I think Krul is better, or at least comparable. Really, there isn't much between their defence and ours, and we seem happy to keep it that way (we're even signing their defenders now). That's why I think it would be nice to have another mobile class option in midfield. Stop a few more opponents early on, because without Mert or Kos that lineup will cave under pressure big time.
Anyway, sorry for dragging the thread off topic.