If I upgrade to Yosemite, can I revert back if I want?

Yes, if you make a backup before you upgrade you can restore it if you want to.

TTeddyau wrote:

I would like to try upgrading to Yosemite, but I'm sceptical as there is a lot of bad feedback with it. So if I do, and I find too many problems, can I revert back to Mavericks?

YES you can. See this thread with 500+ replies

https://discussions.apple.com/thread/6604300?tstart=0

However, you rarely - if ever - hear from those who have no problems with Yosemite.

More RAM is always good if your machine can support it.

Make a backup and upgrade.

TTeddyau wrote:

I would like to try upgrading to Yosemite, but I'm sceptical as there is a lot of bad feedback with it. So if I do, and I find too many problems, can I revert back to Mavericks?

You could install Yosemite on a separate HDD or partition which would make the transition back to a prior OSX a touch simpler and easier.

Ciao.

Csound1 gives the best answer for anyone upgrading regardless of the response to an upgrade. Always back up first. Most people who have had a bad experience with Yosemite either don’t have enough RAM or they are upgrading a computer that is already experiencing problems and think the upgrade will go away. That just doesn’t happen. If Csound1 gave rule #1 for upgrading here’s rule #2: if your computer isn’t stable before you upgrade it, don’t expect it to be stable after you upgrade.

If your computer doesn’t have 8GB of RAM or at least 4GB and an SSD, then upgrade the hardware before you even think about installing Yosemite. Backup first and if returning to a previous version of the OS is lots easier if you have a clone (exact duplicate) rather than a TimeMachine backup. And if you are going to rely on a TM backup then do not let it back up your newly upgraded computer until you are satisfied you intend to keep Yosemite.

There’s an old tech saying “You can never have too much RAM” but that also can assume that you have a bottomless wallet. Unless you are running really hefty programs or several of them, 8GB should be fine.