I don't mind either, as long as they're interesting. Hidden loading screens can be boring, like the elevators in Mass Effect, but some can be alright, like in the God of War games, where you're at least seeing some nicely-rendered scenery as you go.
On the other hand, loading screens are abrupt and can take ages to get past, which makes hidden loading more preferable, but some examples have pretty funky loading screens, like in Devil May Cry 3, where you could attack the loading screen.
On the other hand, loading screens are abrupt and can take ages to get past, which makes hidden loading more preferable, but some examples have pretty funky loading screens, like in Devil May Cry 3, where you could attack the loading screen.