Once again my two bobs worth..
file sizes are doubled when saving in 16 bit...which makes for a lot of storage which is easy enough to get nowadays...
the other down card is processing power and memory on the computer to use these super duper sized photos..so that means normally 64 bit operating systems..as 64 bit can recognise large memory up to the boards specs ..well over 3.2 gig anyway as for 32 bit...Adobe say somewhere you should have 5 to 6 times the memory of your file size ..which if you have say 10 layers open at 100mgs each at 16 bit you will need 5 to 6 gigs of memory just for the photo with out operating system and other rubbish that is going on in the background...if you have 32 bit photoshop it only recognise from my limited memory 1.7gigs unless in a 64 bit system where it recognises 4 gigs.if you dont have enough memory it uses a scratch disc which is slower and needs to be specified and really should not be externals as they are much slower than internal drives often

the other point i would like to make is most times saving in 16 bit is a bit over kill as its only on very heavy work on the photo will it be superior or noticeably, to 8 bit..but the choice is yours about size

now that i have said all that i am confused and will have to rest by ancient bones as an OAP

regards Alan!