After much thought and research online, I decided to upgrade to Sierra. I had backups for everything just in case.
I must say overall I am very happy with the result and I would recommend an upgrade if and only if you have the exact same configuration/setup as mine. System is faster to boot, apps open quicker, UI is snappier.
My setup:
MacBook Pro 15" Early 2011 2.0Ghz, 1TB EVO SSD, 16GB 1333Mhz RAM. Everything else are Apple components. Here are some of my observations (these have been pointed out many times already)...
Positives
- Upgrade itself took about ~40-50 minutes.
- There is a very small amount of jitter with Mission Control or side swiping to switch to full screen apps when you invoke it the first time after doing something else. But its very hard to notice and/or it's not intrusive. Since I use gestures the BIG difference is Mission Control opens as fast or as slow as you complete the gesture, it appeared to 'lag' a bit when I move my fingers slowly. But if I move them quick it looks snappy.
- Geekbench 64-bit Multicore speeds improved significantly! Hitting 9300 on my MacBook whereas I used to get 8700 and the likes before the upgrade.
- Boot times are much snappier.
- Some apps appear to open quicker (many stock apps and some third party apps) and some do appear slower (like Sublime or IntelliJ).
- Picture in Picture is awesome, I use it to watch snippets on youtube while I am doing other work. To invoke it is very awkward -- you need to right click twice on the video and then select PIP menu option. And to think the Mac users never had to deal with "right click" about a decade or more back, in todays Apple we have 3D touch menus and double right clicks. The atrocities...!!
- Safari 10 seems to be the same (although I didn't test Safari 10 on El Capitan).
- Siri works well -- haven't used it much. But it was great pressing and holding Cmd+Space (not holding invokes Spotlight as normal) to invoke Siri saying "Show me the latest email from Sharon" rather than having to click on Mail and type in Sharon. For searches I think this will come in handy provided you don't have an accent and have had luck with Siri in the past. The problem with Siri or any voice assistant is that in the times it gets you wrong, you've already wasted time trying it and it would have been much faster just typing. But they're getting there...
- Storage management: It's "okay". I have set it to empty my trash automatically. I don't pay for Cloud storage with Apple and never will entrust the data there. Google cloud I am much more comfortable with. It was most useful in getting me to delete some older files (as it provides a historical overview of files you haven't accessed or used). I like the Disk Inventory X app UI better though for larger files than Storage Management UI.
- I have more space on my hard drive now as the OS occupies less space.
- Parallels 11 works flawlessly. Had to upgrade Little Snitch.
Negatives
- MacBook PRO runs hotter when plugged in. But mostly due to Photos (see below). This will take days to settle if you have a large photo collection (mine's not too bad around 100GB but its been going at it for about 12 or more hours and still hasn't settled).
- Photos app -- DUH, they are now running some heavy hitting AI algorithms on your Mac. Processes eating my CPU: photoanalysisd, diskkimages-helper, Photos app in general. Note: these only kick up if I connect to power, on battery the CPU is almost same as what I remember seeing in El Capitan. I wish there was a way to turn this off. I use Google Photos anyway for my automatic albums and don't plan on using Apple's photo products.
- Battery life: Haven't tested it yet but plan to.
- If you are a developer and you've upgraded to El Capitan, you know the drill of re-installing command line apps.
Hope this helps. If you are adventurous and have back ups, I'd recommend the upgrade from El Capitan on a similar configuration as mine.