Never been to M4 but I love oasis. Been there on busy nights, weekday afternoons. The first time I went it was a lot to take in especially since it was a busy Saturday night. My gf been there a few times before but she knew what to expect.
For me, it was getting used to walking around other naked people, people checking other people out including yourselves, appreciating others beauty, and realizing that they were all so cool and chill and non judgemental. It was also getting used to playing with my gf while others watched or peeked at u if u choose to play in an open area like the patio or their 2nd or 3rd levels. I could seriously write a book about everything going on in my head that first time.
Our night ended on the patio in the middle of an 11 person orgy. I had trouble staying hard even with my gf playing with me let alone a couple other hotties. I received the best piece of advice from a patron who told me, 'focus on your pleasure, not everything happening around you'. She laughed and thought it was cute seeing how wide eyed I was because a lot of ppls first time will be mind blowing regardless of what u end up doing or not doing in the club.
Daytime on a weekday will probably be a bit slower, so it should ease u in a little in terms of getting used to the surroundings and the whole concept. But I would also recommend to others that if they can go during prime times as their first time, it's really something else to behold. Just remember that every time u go, it's a different experience, some may be amazing, some may be Meh. It really all depends on what type of other ppl go when u are there.