Tor itself is perfectly safe, it is an anonymity network but it also does have it's own firefox based browser bundle that lets you download it and set it up in a simple way.
I would not advise replacing FF or chrome with it, there will be no advantage to total replacement, infact there are disadvantages:
1.it's a bit slow because it has to route through several nodes before getting to the overall internet
2.some sites will not work properly if they see you coming from a known tor exit node, the operators of some sites might decide they don't want anonymous visitors so make some features not work for those coming at it from tor
3.if you use tor too much for things you don't need it for you slow it down for those who really need it
Tor is a safe download but check the sha hashes and such, make sure it is the download the tor website actually meant you to get.
Tor won't protect you from malware any more than other browsers, better to rely on a good antivirus, an anti-malware, an uptodate browser, an ad blocker, a script blocker, an anti-exploit program and cautious behaviour for this.
Tor will help stop your ISP tracking you, and your government and such, but it's not perfectly foolproof. Thankfully the developers behind it, and coders all over the world (including some working for governments as for every time a government wants to unmask tor using opponents it also wants to shield tor using allies), check it for security flaws and update it when they find them. Tor is not perfect but it's being improved at the same rate as new problems are found, the mroe users it has the betetr the anonymity of any individual using it.
P.S. in general you'll only want to use it to visit the normal web in an anonymous way, you almost certainly don't want to go visiting .onion domains. Most of those are a bit dodgy, and there will be a lot of malware there. Tor to visit the normal web is no greater (BUT ALSO NO LESS!!) in malware risk than a normal browser, tor to visit hidden pages is very risky.
P.S. Have I heard a question like this before, something about it seems memorable.
Edited by rp88, 04 October 2016 - 07:19 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB