Which SSD Drive do you recommend

Hello,

Im going to be replacing a Hard Drive for my friend with a SSD. He has a 2010 17" MBP and I would like to ask which SSD you would recommend if he wanted to go with a 500 GIG or 1TB capacity.

He is an accountant, has lots of Quick Books files open simultaneously, but no photo or video editing or gaming.

Im not sure what the capacity is of his machine in terms of whether or not a 6G SSD would be useful if even supported.

thanks so much for your help!

best,

rick