Which browser is considered safer in terms of storing user's data into cache, history etc. ?

Morzilla, as it has some of the best collection of security and privacy enhancing add ons.

Internet Explorer , either if you are using other browser need security setting in browser.

Security of Google Chrome is unbeatable. Sandboxing each tab/process and plugin makes the browser more secure. To understand their security features, watch this video - https://www.youtube.com/watch?v=e0CtgXZSI

If you don't want to cache history, you can run chrome in incognito mode.

Chrome consumes lot of ram but user feasibility or support is excellent, firefox is no less than chrome and better at RAM management, then if you want to go anonymous on browsing, TOR is good, it uses onion routing protocol & proxy chains for browsing anonymously but then internet speed will be decreased, if the bandwidth plan is bigger it'd be fine if not this is no good.  

TOR Browser, because it doesn't store user's daata into cach, history etc...... , and it's based on Mozilla Firefox

P.S : Data Safety depends on the Platform where it is, for example WINDOWS or OS X Platforms aren't safer than LINUX .

chrome is much more secure and efficient to use

Every company does try to provide maximum security of the user information stored in cache, history etc...

So comparing browsers in terms of security of the data is not really  much of a concern  for users who use the internet but the performance of the browser matters. Intternet security can be extended with the use of external applications such as AVG or Norton if required. But when it comes to the performance of the application, Chrome wins.

Mozilla

Google chrome

Safari

 

regarding caching all are the same they store the cache in user profile so it depends on OS, wether you enabled file encryption .. etc . note that usually all application running on the machine with your credential will have access to the caching files. regarding password and user names each has its own mechanism ..1- Firefox on supported OSes (some ports like seamonkey I guess are same) comes with an credentials encryption mechanism using a PBKDF if and only if you set a master password in the default credential managers .. that's make it safe enough ( you need to search about the PBKDF function they use) .. in my opinion this is the most secure way (even default Firefox Sync) save password encrypted in the cloud.2- IE on windows, believe it or not IE uses MS ProtectData API, this API stores the password encrypted with a very strong mechanism, however the huge weakness is that any other application running can have access to these protecteddata with unprotectData API, which requires only to get the protected data name and (salt) .. which are already predetermined, the good thing about IE, is that although any app running with user credential can get access to the password, yet if you take the profile data it is very hard to extract this information .. if you replace the SAM keys to get access to profile files you still will not be able to get this data since it depends on the Windows's logon credentials. so either you lure the user to use some ActiveX control or run any software that is not trusted to get this information, or you have the username and password of the user, or you found a vulnerability or use specific tools to retrieve user credentials (which is possible and effective most of the time specifically is WD-Digest Mechanism is enabled) Safari is very similar to IE yet it uses the MacOSX KeyChain .. access to key chain is by default same as user credentials however I highly recommend that you use different password for keychain, I don't recommend using iCloud Keychain though .. moreover iOS keychain only uses your lock screen password or PIN, so be careful.4 number PIN can be shoulder surfed actually I can't hold myself from shoulder surfing iOS pin .. even six on iOS9 is useless I recommend a long password with regularly changing it every month or two (14 characters at least)3- Chrome stores the credentials unencrypted so I highly recommend never to use chrome credential manager on any OS even mobile finally you may choose to use some credential managers (I highly recommend to avoid any cloud based ones though) .. since most of these password managers depends on username and password to encrypt the password (if they encrypt it) .. most of these vendors are not audited and almost all of them might be forced to give the data out by law if it is ok to use cloud based for you I recommend to choose ones with two way authentication (though that doesn't protect you from attacks on cloud servers and database leakages or court orders or law enforcement or any privacy policy related leakage of data) but it protects you from social engineering and targeted attacks if someone is able to get your credentials to these services. notice that all they need is just a user name and password to get everything else.

In my opinion i can order them as following(up to down)

1-google Chrome

2-Mozilla Firefox

3-Opera

I think the best Google Chrome