The Hilma Hooker, in my opinion, is a better dive because it sank with no 'clean-up', so it doesn't feel so sterile as some of the artificial reefs around the world, it is more like a 'proper' wreck.
I did several dives on it during assignments on Bonaire, including some night dives (awesome, as you are usually the only ones on it, especially if you go around midnight or later), and there are plenty of places to get into which would be classed a true penetration dives, albeit not on a massive scale.
My buddy and I went in every single room and corridor on the wreck, including the engine room (which is a bit tight and full of junk to snag the unwary), and we found at least three decent-sized air-pockets that are large enough for two divers to surface in and have a quick chat (just don't breath the air in there, use your reg).
For your first dives on it, I'd stick to the holds to get your bearings, then you can begin to explore, but stick to what you are comfortable with. Some of the divers on the Hooker with me took one look inside the engine room and wouldn't go in, whereas for me, it was a nice, clean, easy-to-access room compared with wrecks in Scotland and the UK, for example.
Mark