>>>A number of years ago I got the impression it wasn't a good experience (might have been the 3.x days) but Oracle has been putting some effort into it lately with the latest 4.x and 5.x branches. I've only used it on Windows, it's been pretty good.
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>>Can't update my previous message, UT throws an "unexpected situation". Just checked the version of VirtualBox, it's 5.0.24.
>
>That's the version I'm running on Windows. It keeps nagging me to update to 5.0.32.
>
>For lurkers - if you're running VirtualBox on a W10 host, the 5.x branch is required otherwise network support is incomplete.

Just an observation - after a couple of weeks, the W7 kind of crashes. The operation becomes rather slow, the Toad (written in .net, takes six forevers to draw the dozen windows it uses, unless %tmp% is on a SSD), and trying to just hover over the popup when start button is clicked starts opening all kinds of explorer windows. That's when I reboot it before it becomes completely unusable.

Perhaps there's a memory leak in the screen savior I wrote (using GDI and iPicture interface), I usually run it on weekends and I guess after displaying some 40000 pictures it tires down the machine.