Accounting Traffic usage best practice offer

Dear Geeks.
Hi, i have one very important question that search much for that, but unfortunately I cannot find one specific and always true answer.
What i need is accounting the mikrotik traffic usage (per interface / queue or every thing that I can simple calculate what is really my usage).
It seesm simple but i found out that is really long story.
I found out mikrotik by itself has some problem using stats when it reboot and turn off and turn on (stats maybe reset).
however the monitoring software is different story. i myself using cacti. but many of them are buggy specially for connecting mikrotik. and some stats may not show correctly, wrong data and etc.
my question are bellow:

  1. does Mikrotik Usermanager itslef can solve the problem truly (specially in case of rebooting routerboad and something like that). does the stats are reliable?
  2. whats your offer in case of want to use accounting software. (reliable opensource tested works with mikor preffered)?
    I also hear about some name like observium and etc… but stability and bug free is main concern
    Thanks in advance.