I bought this MFC-L5700DW to supplement an older MFC-8220 that has been a workhorse for me since I bought it in 2006. I have a law practice, and am a heavy paper user. The new MFC-L5700DW was initially purchased so that I could handle network printing of Apple IOS products, but it has proven to be so much better than I could have imagined.
I connected my MFC-L5700DW to my network via ethernet cable so that it can do wireless printing (I don't want to rely on the machine's WIFI - I'd rather use my own wireless routers so that I can have better coverage in my office space), but I also have it directly connected to my laptop. The machine can handle much, much larger stacks of paper for scanning / faxing than the older MFC-8220, and it prints extremely fast. I constantly use the print, fax, scan, fax to PC functions, and I like that it can save faxes on the machine when my computer is turned off. I also like the fact that i can print saved faxes directly from the machine (instead of downloading saved faxes to my computer from the fax machine - which takes a VERY long time). The machine scans in color, and black and white, and the black and white scanning function is very quick (color scanning - which is much more memory/CPU intensive - takes much longer. However, the scan quality is excellent).
The ONLY thing that concerns me about my machine is the fact that the paper trays are made of VERY thin plastic. I was worried that they might easily break. However, the paper trays slide out very easily. Nevertheless, I always pull the paper trays out gently. The machine isn't too loud, as some people have reported. It does require a decent power draw when it starts printing, but I have my computers on a battery backup, so I don't have any problems with computers blinking out. Some people have reported that scans come out crooked. However, you have to push the paper all the way down in the Automatic Document Feeder until it bottoms out. The paper will stop initially when you push it in the ADF, and then you slightly push one more time until it bottoms out. This will make straight scans every time. Now my MFC-8220 sits on a shelf as a backup multi-function machine.
Overall, I can't tell you how pleased I am with this purchase. It is excellent in every possible way. I would buy another again - without hesitation. Last comment - if you do the math on the consumables (toner and drum) this is one ECONOMICAL machine. Get one - you won't regret it. FYI - I bought a refurbished model, and it is PERFECT.