Folks:

For historical reasons, I have "Site A" on "Hosting Account A", and "Site B" on "Account B", totally independent accounts with the same vendor, Bluehost. Both are primary domains. Now that Hosting Account B is just about to expire, I'm considering letting it disappear and moving Site B to an Addon domain on "Account A".

Both sites are non-commercial, narrow-interest, very-low-traffic, hundreds of page views per month. The file weights for the sites are non-trivial, especially as I like to install specialized CMSs in subdomains. Since Bluehost allows unlimited hosting space there should be no issue with the file load, except I've seen hints of an issue with total file count, maybe 50k files -- which I'm not currently close to hitting, but might eventually.

My question: what are the pros and cons of using separate accounts versus hosting Site B as an addon domain?

Obviously, using a single account is cheaper by half, and I know that my authoring environment (DreamWeaver CS5) complains when it detects nested source trees, telling me "Synchronization" might fail in such cases, but I don't depend on this feature.

What other factors should I consider?

TIA