Uno or Due for voltage measurement

First I am new to micro controllers, so if I dont make sense I apologize, but I think I am picking it up fairly quickly. I went a little overboard when I started playing with arduino and bought a bunch of sensors that I will probably never use in a real project but I thought the more I have the more I will learn. Kind of overwhelmed me at first, so I took a step back and just started building some small things that I could make use of. I have already gone through a lot of different tutorials and made a few of my own little devices, for my farm. Currently I have two Uno boards and have been playing with them. I know enough right now to tinker, and make some basic devices.

I have been doing some research on a new project that I am working on and have read that the uno is not really capable of getting accurate voltage measurement on its own. Some say to use an LTC6655 as mentioned here . My project will require me to read the voltage that ranges from 0vDC to 5vDC. I need to make sure this is a pretty accurate measurement for the next stage of the project. I have four inputs that I will be monitoring each one will be between 0 and 5.

My question is that if the limitation of the uno is in reference to its chip when reading voltage then would the due be the way to go on this? Would the Due provide for better measurement of voltage? It seems to me just based on what I read that the due would do better than the link above??? I know the clock speed will help with my project so if is the case the due is getting purchased.

Sorry for the lack of knowledge on this one or if it doesnt make any sense.

You want 10 bits of resolution? Each step being 4.88mV?
12 bits? 16?
Very easy to add an SPI (or I2C) interface ADC that will give you the higher resolutions over a 0 to 5V range. Example for an 8 channel 12-bit ADC:

MCP3201 & MCP3204 for 1 channel and 4 channel also available I believe.

After doing a little more research, I am not going to use the Due for this project, however I am purchasing it to play with. Since the due is only capable of Native 3.3v inputs I decided against it for this purpose. I am going to also buy the mega to allow me some more inputs for this project.