<pessimism>
My fear with all that android compatibility (layer) on the phone is, that most software developers won't have interest porting their gems to Sailfish.
What's the appeal as the phone is running the android version fine?
It would be again the users [thanks to TMO!] doing their own stuff as it was for harmattan/freemantle.
</pessimism>

I apologise if you knew this, but here it goes anyway: whenever you notice your phone consistently slow (not those glitches that happens with certain pages's javascript for instance), open a terminal and type "free" - share the results and we'll figure out what's doing.

I'm working on the assumption that Jolla did this and much more in their tests.

Well, you don't get a bunch of things that Sailfish gives you, such as:
- Full screen usage (Android apps will have to have 3 buttons drawn at the bottom)
- No pulley menu
- No "multitasking" tasks on the multitasking screen (e.g., play/pause/next in the Music Player application)
- No access to the deafult UI components of Silica
- No integration with Ambience
- Marc also hinted that "of course" native applications will run faster, but we don't have stats for that as yet

You make it sound like if they did create a phone with a quad core CPU and 3GB RAM, that they'd decide to cut costs and include a 500mAH battery.

Usually battery isnt big because of size not cost.

What he said

Wrong. Iphone 4S that I use from time to time has a great screen and keyboard. Very few mistakes. N9 was by far the worst. WP is in between. Never tried copycat Android

Really? You think by having the output of free the limitation of 1GB RAM on the N9 can be covered? There is a reason things like FasterN9 exist. Let's not hide flaws and say 1gb is sufficient when the N9 has shown that on boot system libraries and apps/services itself take up 700MB of RAM.

Maybe Wayland brings down the RAM usage to achieve a UI of 60fps because this clearly failed on the N9. Want examples? Refresh your feeds and scroll the home screens; 10fps. Sync all mail accounts and minimise Fenix, try opening phone app etc.

The N900 has been limited among other things mainly by its 256MB RAM, the N9 as we understand now had to have a custom chip to get the 1GB of RAM required and now the Jolla is unfortunately again limited to 1GB of RAM. In an OS that is geared towards true multi tasking, the RAM is really important compared to Android etc.

Does that mean I won't get the Jolla? No, I still want it as it looks the best thing but I won't be surprised with the device being limited by RAM (again)...

Did I mention that I have 3 GB

Ok, this was the last time.

Who is responsible for that Google doc. Their grammar == mine.

No, but free gives you an idea of how much memory you have free, how much is being swapped and how much is being used for fs cache. I hardly ever got to 700MB myself, and the display capabilities of the GPU are another matter - the Raspberry Pi can play videos at 30fps/1080p no problem with 256MB RAM and 512MB RAM, so very little to do with memory.

I actually know why my N9 slows down when it does, and most of the time is not the amount of applications open but some heavy Javascript here and there. Having said this, I'll give your use cases a go and see what happens.

I do agree that a more thorough diagnostic/monitoring application will give you better information, but was just suggesting an easy one. The command free is used quite widely in Linux environments to give you a very quick and light weight snapshot of the memory situation. I don't think it should be disregarded.

EDIT: I stand corrected... you have to use "top" to see the amount cached, for some reason it isn't implemented in free (or maybe if you use bash instead of bb).