Before, I didn't have to choose a location, it already went to F:\Program Files\Ableton\, so all I had to do was hit next.
You did at least once. The default intal location for Live has always been on the C: drive. I guess you once chose the F: drive?
Now, it's C:\Documents and Settings\All Users\Application Data\Ableton\Live 8\ the last 8.3 betas.
Last time I chose to "replace", but then at the end it said the installation couldn't be completed because there were similar files iirc.
That would be a wrong behaviour of the installer. We'll check, let us know if you can reproduce that.
Putting in a custom directory isn't a big deal, it's the conflict to how you're saying it should work.
When I choose to update from within Live, it still opens the browser, download the new beta, install and fix the directory, which didn't have to be done before. So, auto-updating doesn't work for me here, but it is a beta so maybe it isn't fully realized yet.
It's been full installation each time with 3b1,2 & 4.
You're describing a manual
installation, not the auto-updates I'm talking about. You are using "check for updates" in the Help menu, which is a manual step to trigger a manual update.
Auto-updates do not require any action on your part. Once enabled, Live updates itself on startup, and you shouldn't even notice.