Ibrowse 2.3 was one of the browsers I tried a year or so ago when I tested the site compatibility, but since it doesn't handle css adequately it made a complete mess of the layout rendering the page unusable. Remember the old NetPositive browser on BeOS? Same problem, same result.
I thought one of the main reasons for coding everything related to layout in CSS was to ensure that the page worked nicely (to browse, not looking perfect layoutwise) even without CSS-support (in this particular case I do not know which site is discussed, so I can't comment on that very issue).
Though, my experience says that more and more sites seems to work really well in IBrowse 2.3. I guess it could have something to do with sites being more and more 'correctly' coded thanks to Internet Explorer losing quite many users to FireFox and Opera (and other alternatives). Internet Explorer really helped in screwing up the net with all its non-standard HTML e.t.c. support (which made people coding less and less accurate for the web).