It is, and it should be, the poster's choice of filehosts since they are they ones doing the giving.
I have both Hotfile and Rapidshare Premium accounts, but when I post (not often enough, I know) I tend to use Rapidshare, simply because my personal experience of Hotfile is very poor indeed. However I know that some other people have had a bad experience of Rapidshare. Perhaps I should post to both, but I only have 512Kbps upload capacity with my ISP..
Hotfile in theory is good for downloads (fewer clicks, fo example), but for some reason I (and it seems quite a few others) get almost non-existant download speeds on Hotfile till the early hours of the morning, and nothing I can do seems to change that. So I too am glad when someone uses Rapidshare and my heart sinks when I see Hotfile.
Now if someone could find a host which is good for uploading and good for both premium and free downloads I would personally come and give him or her a kiss. Whether that would be an enjoyable experience is another matter......