SSD 2.5" or M.2 for Notebook

[Cpt.Fox]

Hi guys,
im looking for a new SSD upgrade for my dad's Lenovo P50 Laptop, he already has a 2.5" hard drive so i would have to remove it to install an 2.5" SSD, the other option would be to buy a M.2 SSD and then we wouldnt need to move the files and OS to another Drive, well maybe only the OS. Considering convenience and value , What do you think is the best choice?
Here are some drives i found available, i dont know which brands are the best nowadays and i'd think write speed is more important:
m.2
https://www.spdigital.cl/products/view/60609
https://www.spdigital.cl/products/view/56786
https://www.spdigital.cl/products/view/58948
2.5
https://www.spdigital.cl/products/view/59571
https://www.spdigital.cl/products/view/58948
I appreciate your help

 

[seagate_surfer]

Hello foxslink, question you need to ask yourself is for what will you be using the drive? Storage I presume as you are interested in write speeds. Both options you present will work but you need to check if they are compatible with the laptop. Have you considered an external drive as well?