We bought this fax machine due to my wife's need for occasionally sending and receiving faxes for work. We didn't want to spend much money and we have only one phone line in the house.
We picked the Brother Fax 575 simply because it was half the price of most of the other brands / models. Now I know why it's so inexpensive; because it's a very good one.
My first annoyance is the answer modes. No matter which settings I choose, it doesn't automatically detect an incoming fax and answer it. If it did, then I could leave the machine plugged in and use it like I expected it to work. Since it doesn't work that way, I need to plug it in only when we know someone will be sending a fax.
Another problem I see with it is the image quality. As to faxes sent, they're not very high resolution and depending on the receiver, it can be hard to read. As to ones that we receive, they're not always readable, depending on the font size.
The last (of the major) complaint I have with it is the cartridge used for printing faxes. While it uses plain paper, you only get about 50 pages printed before having to replace the cartridge. That's going to be rather expensive for printing.
Overall, I do not recommend this fax machine at all. if you need a fax machine, spend the dough and get a multi-function device like those from HP.