Anybody here is using the new Mac OS Sierra? If so, Any bugs? or problems at all? Any disadvantages?
What worries me is that it might cause my softwares not to work and will not recognize my hardware like SSD or Max RAM.
My current specs:
While it is always possible for bugs to occurs in major upgrades to the macOS, it will almost never have any issues with recognizing things like your SSD or max RAM. Beside the possibility of unexpected bugs, the main potential issue with a major upgrade is incompatibility with some software programs. Typically, however, software programs that might have issues with a new macOS major upgrade are more "low level" stuff like utilities. Your more main stream "productivity" or general applications (such a Microsoft Office, major games, Photoshop, etc) will not have any major issues with new versions of the macOS. It will be more applications like iStat Menus, SuperDuper, etc that might have some compatibility issues with a new version of the macOS. BUT...most of those types of programs will typically issue updates to make them work fine with the new version of macOS prior to the new version coming out or just after the new version comes out. After all, they tend to have at several months with at a beta version of the new macOS prior to it being released to start working on updates.
So, generally speaking, you likely will have no major issue with upgrading to Sierra if you wanted to do so now. If there was any major issue, there would have been tons of news reports by now (like there was about the iOS 10 WiFi upgrade download bricking some people's iPhones last week). You likely will have no issues at all other than maybe getting used to the new features. There is a chance that there might be some minor bugs. If you are worried about minor bugs (or some thing worse), then just wait a while until Apple releases the first patch. Personally, I tend to wait a little bit to let Apple work out some of the kinks they may have...or as I also put it: "Let other people be Apple's test dummies".