To me people suggesting that you need to root or jailbreak your phone tells that there are some glaring issues with the OS. Before Android Lollipop I felt rooting was very much necessary because the system didn't work as one would like. Now my main beef on stock Android is that the yellow charging LED cannot be turned off (whoever came up with that in the first place is an idiot - who wants a bright light in their bedroom during the night?).
I would suggest that by the same token, every manufacturer's skinning and customizations would indicate that the manufacturer found glaring issues with the Android OS, so by those standards, Samsung, HTC, your carrier, etc don't think that stock Android is that great, so they do the equivalent of Android jailbreaking for you by re-skinning the whole thing in TouchWiz, Sense, etc.
I wouldn't write off jailbreaking for a means of completely changing the way you use your phone. It's been a long time since I've jailbroken with the old shiny iPod touches, but you can get a lot out of it like face-recognition unlocks, re-skinned home screens, retro-fitted 3D touch swipes, etc. This is a little bit old since it's for iOS 8, but if you want to check it out, this is a pretty good example of some jailbreaking tweaks you can use:
http://phonerebel.com/top-100-ios-8-cydia-tweaks/
If all you really want is emulators, then you could easily instead just install the apps using one of the available services like iemulators.com. They use enterprise certificates to side-load apps without the app store.
just switched yesterday..
at start, it's not that easy to get used to being "locked".
i still feel limited.
for example: i'm trying NOT to install Itunes.
but there's not other alternative way to upload music somehow.
not through cloud. trying to check out Wondershare but it still doesn't support 6S.
what about Dropbox? is that also limited only on the Iphone?
so i have to use ONLY ICloud?
things like that can make me mad, but i'll have to get used to it.
but these are almost the ONLY things i need to solve somehow.
i tend to watch most of my video and audio via streaming so don't need Itunes.
i guess i'll have to settle with some Icloud payment regarding photos uploads & videos.
but i'm used to handle it all through DropBox.. so a bit annoying.
There are a few apps that allow you to manage music without iTunes. I personally prefer iTunes since it gives me some flexibility cloud-wise to slap my music in iTunes, hand apple $25 for iTunes match for the year, and now I have unlimited (up to the max library size of 25,000 songs which don't include the songs that iTunes can match to equivalent albums on the store) streaming of my lossless (converted to 256kb aac) collection from iCloud. A similar approach would be to do it with Google Music, but what you're probably looking for is VLC.
VLC will let you steam from Dropbox, Google Drive, etc. It will also let you make a web interface on your LAN to upload files to.
VLC also lets you open webm files from Safari, so you can browse websites that use that format in Safari if you're willing to download the video to vlc to view.
There are a few apps on the app store like USB Sharp that will allow you to drag and drop files onto your phone to take with you.
2. very weak email handling in stock Mail app for accounts of Exchange, Hotmail, Gmail,
I can honestly say that I haven't had too many issues here on the iOS side. I'd say that I've had way more issues with mail.app on the Mac side. There have been plenty of times where I'll search for an email on my mac and it won't show up, but when I'm on my iPhone I could find it easily, and the search is across all of my mail accounts, so I can usually find what I'm looking for even if I forget which email I used. I'm also a big fan of the unified inbox, but I know it's not for everyone. I would like to see more filtering available on the phone side. I've switched to using server-side mail sorting when I want to set up filters.
6. not being able to open some websites in Safari,
I don't remember seeing any specifics, but if you're having issues, sometimes people try to "optimize" the page for iPhones and break functionality. Also, the content blockers for ad-blockers (If you're using any) can sometimes block an entire page. For both of these issues, if you hold down on the refresh button, you get a menu for refreshing the page without the content blockers (which resolves the issue most of the time for me) or to open the desktop version of the site instead.
I've used these two settings to browse pretty much anywhere that isn't a flash game.
9. no physical return button, is often a challenge,
If you want to do pretty much anything with going back, swipe from the left edge. Since you have a 6s, this goes double since you can 3D touch the edge while swiping to switch between apps or just go to the app switcher.
I would also argue that this app switcher access and method of going back can be a lot more convenient than Android with a big phone. The swipe from edge can still be accessed one-handed while you are gripping the top of the phone with the edge method. If you use a dedicated button, you would have to shimmy down to press it to get the same functionality. There's also the UI argument of the edge being an infinite-sized button while the button is a limited-size point, but that's another topic for another time (here's looking at you side-menus of Windows 8).
Also I HATE that I can't access app settings from the apps themselves and instead I have to back out n hit the settings icon...-_-.
This is up to the developer of the app, but I can honestly say that I haven't gone to the settings app to adjust settings for pretty much anything other than Apple services.
Also, while it may seem a bit fanboy-ish of me to suggest, the WWDC and iPhone release keynotes are HUGE resources for finding out about "hidden" features of the os like what swiping from the edge will do in different apps. For instance, if you want to know about some extra mail app features you get with 3D touch, watch the latest keynote,' and you'll know just about as much about 3D touch features as an Apple Retail employee will. I've watched every keynote since before copy and paste were introduced to the iPhone in iPhone OS 3.0, and there have been quite a few times when I've been able to help people out just because I learned about a feature from a keynote.