I've used the first two and never had any problems. Can't say yea or nay about the third one. As for the add-ons, if you're careful during the installation process you can usually avoid stuff like the wonderful Yahoo! Toolbar by opting out. It pays to go slow and read the fine print.
Freeware generally falls into these categories:
1) Really, truly free. Being the skeptical type I always wondered about that. After all, the TANSTAAFL principle holds true so often. One thing I've found after going back to school in my declining years is that there are a lot of quite talented programmers in Universities. (Sadly, I am not one of them.) They often have a major project they need to complete for a class and to keep from going completely bonkers they pick something which is actually useful. (I've had problems like generating a list of 100,000 random six-digit numbers, then sorting and searching them. They are useful tools for a programmer to have in his arsenal, but there isn't much point to a standalone program like that in the real world.) A good programming student (years ahead of me) can whip up something quite professional. After they're done and get their "A", they often just throw the program out there, content with the satisfaction of seeing hundreds or thousands of people download it. (Some of them even say thanks.)
2) Adware. It works, but you get the ads. Hey, television was like this for forty years. How'd you like the price, though?
3) Virtually free, if you are careful. See the note above about the Yahoo! Toolbar.
4) Nagware. You'll get a popup, usually when you least expect it, reminding you that the Pro version is "so much better!". Sometimes it actually is.
5) Crippleware. It runs, does the basics, but the tantalizing feature you'd like to try is grayed-out. They're counting on you finally giving into temptation and coughing up for the full version. It's just like Nagware, but more subtle in its approach. I've seen video converters that will do the first ten minutes of your movie, then stop and tell you that only the pay version does the whole thing. Some of them end up being pretty close to the next category:
6) Out-and-out fraud. Yeah, the download was free. So was the installation. Then you run the sucker and it tells you that you can "see the results by going Pro!". They're banking on the fact that after going that far you will give in and pay for it. Kind of like the chatty girl you happen to run into at the club who you find out is also a "Pro" - but only after you're getting in the car together. Either one may give you a virus, too.
7) Theft. That chatty girl in #6? When you get out to the parking lot her boyfriend hits you over the head with a big stick and steals your wallet. Thought you'd downloaded an mp3 tagger? Welcome to the Blaster Worm, sucker.
