depends on your files. If you have a lot of big files on your drive larger clusters will give you better performance and better drive size utilization. If you have many small files then it's better to have smaller clusters.
If you have a 3k file on your drive and 4k cluster size, than 1k of that is wasted. If you have 1,000 of those 3k files then you're losing 1,000k of space.
If you have a bunch of 2gb files and a 32kb cluster size then your drive will be able to read the larger clusters much more quickly, and you will get better performance if the files aren't very fragmented.