I've been using it on all of my computer without any problems. Remember you won't see any positive comments here. Everyone here is complaining about a problem. If you want a good experience with any upgrade or update first make a backup from which you can boot the computer. If you are installing an update, like 10.10.3 for example, always download and install the Combo Updater - OS X Yosemite 10.10.3 Combo Update. Before you install any update or upgrade over an existing system you should do this:Repair the Hard Drive and Permissions:
Boot to the Recovery HD:
Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.
Repair
When the recovery menu appears select Disk Utility and press the Continue button. After Disk Utility loads select the Macintosh HD entry from the the left side list. Click on the First Aid tab, then click on the Repair Disk button. If Disk Utility reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit Disk Utility and return to the main menu. Select Restart from the Apple menu.