How to upgrade mATA of a table?

I read an instruction How to Replace or Upgrade the SSD in Your Windows 8 Tablet
for simply replacing the mSATA SSD of a tablet to increase the storage capacity.

As I checked on amazon the price of mSATA is cheap and high capacity (500 GB) ones are available for fair price.

1. Do all tablets have standard mSATA SSD?

2. There are different models of mSATA SSD, namely M4 and M500 ( Amazon.com: Crucial M500 240GB mSATA Internal Solid State Drive CT240M500SSD3: Computers & Accessories and Amazon.com: Crucial m4 256GB mSATA Internal Solid State Drive CT256M4SSD3: Computers & Accessories). What is their difference, as the prices are significantly different.

3. Is it reasonable to buy a cheap tablet with low capacity, and then replacing the SSD, as tablet with capacity larger than 64GB are too expensive. I did this for laptop, but the structure of tablet is slightly different and I have no experience.

 

Probably no tablets (or at least very few) will have mSATA SSD's installed.

Most are the excruciatingly slow eMMC variety and not worth upgrading for performance reasons (they're still limited by the slow as molasses eMMC interface, even if the drive is better than stock).

 

I bought an Asus T100 it only has 32gb of Sandisk flash memory, i found a teardown and it appears the flash is soldered to the motherboard.

John.