My only gripe is that it looks like cloud storage is the only storage option from within the virtual 360, is that right? That's fine by me but for now 360 cloud storage is capped at 500MB and that won't be enough. Here's hoping they make it unlimited like Xbone which would obviously benefit actual 360 consoles as well.
I have over 100 games for 360 and I moved all the save data to the cloud. I think it took up a little over half of the 512MB available. You should be good.