I ran the upgrade from Lion to Mountain Lion today. It went smoothly; took less than half an hour. To prepare, I did a Repair Permissions on the drive with Disk Utility, and then ran Disk Warrior 4.4, the application I use to check and repair directories on all the Macs I service.
Sure enough, mine needed the run; the usual Volume Information Block error was found and fixed. Had I not done that first, the installation might have failed and rendered the drive inoperable. Simply put, you should always run Disk Utility before upgrading, even if only to Verify Disk. There may still be errors present, but it's better than nothing. Disk Warrior costs $99 and is a worthwhile investment for people who want to take care of their own Macs.
Upon restart, I was notified that two of my apps were not going to run in Mountain Lion: Little Snitch and Snapz Pro. Little Snitch has an update available, but Snapz Pro does not. According to the Snapz web site, some of the features work but others were disabled to prevent a kernel panic (that multi-language overlay that appears telling you must restart your computer now). I signed up for emails notifying me when the updated version would be ready.
It's nice that Mountain Lion can perform this check and disable incompatible software before it crashes your Mac.
Safari Back to its Bad Old Tricks
The problem that appeared to be repaired in Safari 6 for Lion has reappeared in Safari 6 for Mountain Lion. Right after the upgrade I went straight to my 25 "Open in Tabs" list of daily comics and there it was - the dreaded "Web pages are not responding" dialog I wrote about in my previous report.
That means that either what was fixed in Lion re-broke in Mountain Lion, or it was never fixed at all and I just didn't experience it during my brief test.
AppleMail - No Drag-Selecting
Previously I could select a range of messages in the INbox (or any other mailbox) by highlighting one message and then clicking in the white area between From and Subject and drag down. Not highlighting first would turn the cursor into an envelope, signifying that the message I had clicked on was being Moved somewhere, i.e. to a different mailbox. Also, dragging directly sideways would invoke the Move cursor.
Now the Move cursor is always invoked. If I want to select a range of items it requires a click on the first item and a Shift-click on the last, selecting the items in between. The usual Command-click on each item selects the item clicked without de-selecting the previously highlighted item. This has always worked that way, and is the same way you highlight items in the List view in a Finder window. I consider this change a loss in functionality.
I still have not found a keyboard command for "Open Next Message." Why something so simple and basic has not been implemented is beyond me.
Return of Save As...
Lion took away the SaveAs option that we have had since the beginning. Their substitution of Duplicate or Rename was confusing and less functional. Good news is that it's back. You must just hold down the Option key when clicking on the File menu to restore the command. To do it via keyboard, you hold down Command, Option and Shift keys while typing an S. That does the same thing.
At last, a simple app that you can use on your Mac to store any information you want also available on your iPhone or iPad. In the past you had to tie it to the notes in Mail, which were not reliably transferred to your iDevice and required opening Mail to access. This is a feature that existed in OS9 and before, a simple note pad under the Apple menu. Of course there were no iOS devices to sync to, but one could sync to a Palm device back then. Personally, I fixed the problem by keeping text files in Dropbox. That worked fine, but this is a more integrated solution and it is certainly welcome.
The best news is that I don't notice much difference in the general operation of my Mac at all since the update. It feels the same, runs just as fast, and Safari seems to be the same as it did in version 5.1.7 under Lion. I was really sad to see that it still isn't fixed.
There are a lot of articles and blog posts about Mountain Lion around. I would recommend you visit sites like Macintouch and MacSurfer Headline News and fill in your information with them. No need for me to reinvent their work here.