I had previously had bad experiences with divided tanks, but I live in an apartment that's less than 250sqft, so when I brought home my Milton, I had to split a 10gal since fitting another 5.5gal into my tiny space just wouldn't have worked. Personally, it's not my favorite, but they don't flare at each other that I've seen and they're both healthy. If I could have separate tanks for them, I would.
If you'd like to keep two guys in one tank, it's a quick, space-saving solution. If you've got the space for more tanks or just giving Raz the 10 to himself, that's probably the best option.