You might have realised from jules' posts, though not from (the absence of) mine, but I'm back.
Here's a well-written account of the strengths of the EGU's open peer review system, from one of its strongest advocates (and Chair of the Publications Committee). The journals continue to grow steadily and (moderately) profitably, and their success can only be helped by policies such as this. It is worth noting (again) that the publication charges of the EGU journals, which make their papers freely available, are only comparable to those of for-profit journals which then sell on the papers at a huge additional profit. Many paywalled journals do offer open access, but only for a fat additional fee. It is hard to see how they add value to the publication process. Both approaches rely on unpaid reviewers to do the bulk of the (post-authoring) work.
The issue of open review is additional to the open publication, of course. Uli makes strong arguments for the EGU system, including that although the number of unsolicited comments seems low, it is far higher than you get in the traditional journals. However, writing "Comments on" is hardly the same thing as suggesting changes to the design of the figures or even asking the author to cite one's own papers more :-) I do like that he doesn't pull any punches in slagging off the silly Nature designed-to-fail "experiment".