"Rather modern" or "recent" is very subjective and relative. Sure, it's based on web kit, an older version than the one in use on most systems today and there's no flash support, no download manager, no plug-ins, and CSS support is flaky. And when I come home and need a real tool to get real work done, I switch on a PC running Linux or Windows. If I want to play games or use a toy, well, there you go. There's MOS or OS4....or a UAE variant. Oh, but wait....no game development there anymore and no Media Center app that can play DVDs or BluRay/HD.
Err, i think you're greatly mistaken here:
First, the webkit revision in OWB 1.10 is likely more recent than yours, since i use nightly revisions. OWB 1.10 is based on 2nd september 2010 WebKit SVN state. Isn't that recent enough?
Besides, it has a full download manager with resume support and remembers downloads across sessions, it has plugin support (swfdec for Flash), it supports HTML5 video (Theora, H264, WebM), it has a very conform Javascript/CSS/Whatever support (it scores 100/100 at Acid3 and 198/300 at html5test.com... try the same with browsers like firefox or IE

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MPlayer is perfectly able to play all kind of media (DVD, streaming, audio and even HD H264 files where OSX crawls miserably), ...
Are you sure you don't confuse OS4 with MorphOS too much here?
