From your own experiences, which are the best/worst browsers and add-ons?
Which good and bad aspects do you find in them, eg level of or lack of safety, security, privacy, privacy policies, number and level of customising, etc?
Which browsers have (the most) add-ons?
At least Firefox, Lunascape, Opera, Chrome, Internet Explorer and third-party custom equivalents of them (especially relating to Firefox) have a variable number of add-ons, depending on the browsers in question.
Are there any signs that give away or that we should look out for that determine which browsers and add-ons are dangerous?
I don’t yet know of any conclusively rogue browsers, but I sadly have no doubt that, like other types of software, there will be bad browsers and add-ons around that appear genuine on the surface but install hidden malware and/or spyware and other parasites.
As to add-ons, this is a very grey area. Not all add-on developers have their own web sites, which may or may not amount to anything bad in their software, and only a selected number including Ghostery give users the opportunity to change options. Although no guarantee of ensuring safety, a good number of positive reviews against negative can often help in determining which software is safe to use or best to avoid, and some add-ons are also downloadable directly from their own web sites.
I don’t know if add-ons that have say a "Coupons Helper" and “Play Strategy Games” in the menu (by right clicking on its icon), which must be pre-installed and which also exist as separate add-ons or equivalents, eg “Free Games”, are safe, as I've never literally sought any downloads with coupons and games (these also exist as separate add-ons), but these are some of the many aspects that relate to browsers and add-ons.