I've been using it for a couple of years and have never had any problems. It's a Chromium browser, so you need to be sure and get (and keep..never update) the older version that supports flash (NPAPI). Everything after version 10.0.7.0 will only allow pepperflash (PPAPI). Unless you specifically downloaded the older version, you have a current one. If you get the older version, make sure to disable the pepperflash, and leave the other flash enabled. Very smooth and never any issues in game client due to browser. Also, what works on some people's computers may not work well on other's computers. Comodo IceDragon is also a good one.
I read on Adobe's site that they were killing Flash "by 2020". What they said was they were stopping support, udates, and patches..which is not really killing it to me, but from a safety standpoint, I guess it's our warning.
PS..I use filehippo to get older versions of software (and Slimjet)