so i haven't been to a rainbow gathering in quite some time, so feel free to take what i say with a grain of salt.
i've been to 2-3 nationals and about the same amount of regional gatherings, but i somehow always manage to show up late, so that might have skewed my opinion as well.
first the bad stuff, i mean i got giardia from a food camp there one year, and the year before that i got most of my gear stolen. so those both sucked ass. also, who jacks things out of someone's tent, especially a hoodie in the cold ass mountains? anyways, the nationals are the big big event so you'll get a LOT of shitheads that have no interest in the culture and just want to get 'free drugs and loose hippie pussy'. it seems that regionals, being smaller events are less susceptible to these kinds of people. also, from what i understand, a lot of the original elders are dying off, so i think there's been a changing of the guard and that's been affecting the event as a whole.
now i don't believe in hippie dippy spiritual crap, so there's going to be a lot of shit going on at rainbow that just doesn't interest me; if you feel the same, i don't think you're going to have that great of a time there. that said, what i really DO like is the individual camps at the gathering. anyone can start a camp about anything, so you get a lot of camps that are regional or theme-based (like free coffee camp) and i really liked going around to all the different camps and just meeting new people and other travelers. also, i've heard a lot of the events (that i always seem to miss somehow) are pretty wild and can get into a crazy party mode which might be interesting.
overall, while the rainbow gatherings have some kind of mission statement centered around ... well... hippie mother earth stuff, you're not going to actually see any of that in the gathering itself. which is unfortunate, and i feel like for the most part it's kinda lost it's way and for a long time hasn't really understood why it's doing what it's doing besides fueling hippie dead lot culture (imagine gutter punk hippies, that's 'dead lot' culture aka people that follow the grateful dead).
anyways, i really think it comes down to what you want to do there and where you find yourself on the scale from hippie to punk. if you're more of a punk ideology/culture/music wise, you're not going to have as much fun if you're a om-ing hippie seeking enlightment.
as for myself, i've been planning on giving it another go this year. my gf has never been and we have a lot of friends that are meeting up there. that said, we have a lot between us and then in the next three weeks (moab, yosemite, denver, driving up the 101,etc) that we might not make it in time because we're having too much fun (which sounds like your position as well). so if you miss it i wouldn't worry too much about it, but if you've never been, i'd also check it out. if you can't make the nationals, there's a regional gathering just about every month so i'd find one of those and go check that out.