The daime ceremonies are divided mostly in two types.. Concentração (concentration) and bailado (dancing). The first one happens every 15th and 30th of each month, and you spend all the time sitting down, basically. You can go to the bathroom if you want, but should go back to your seat as soon as possible. There are generally 3 doses served during the ritual, with a considerable time in between each. Basically during the whole ritual it keeps alternating moments of pure silence, and singing and playing of the hymns. There is no 'sermon' such as in churches. The message is passed through the hymns, which talk about spiritual evolution, the 'mistery' of existence, the forest and helper spirits, ayahuasca, but also about jesus and other incorporated catholic figures. Some of the hymns are very very beautiful, others not really.
During the bailado rituals which happen in different dates, you spend the whole ritual dancing in a pre-determined manner, everybody together, and singing.
I have my criticism towards daime.. For example, even though the hymns can be nice, I generally dont like to listen to anything with lyrics during an experience. I go so much beyond words and usual thought patterns that words from singing 'hold me down' somehow... With the icaros of indigenous people its totally different, its not about the words but about the sound patterns and vibrations that bring specific visions, I enjoy it much much much more.
Another thing I dont like in daime is the feeling I got from many 'daimistas' that they are always trying to 'convert' you. I want people to respect each other's ideas, not try to force their own, even more if they are entheogen-related people. It sometimes gives this impression of a cult. I do know some important exceptions, though, like 2 very good friends of mine that are fully respectful (but appart from being in daime they also participate in indigenous rituals, so dont know if thats a coincidence or if daime-only people are more fanatic than the ones who are a part of it but are also part of other entheogen 'sub-cultures'
Another thing I dont like in daime is that, also because its too big, they have to 'control' things. So for example, in a ritual, they have certain members who's job is to look out if everything is running as it should. I dont like having a 'supervisor' or 'guard' type of person looking around when im tripping. Once there was a situation where I was standing up in a corner during the concentration ritual, because I was about to vomit, and one of these members came to tell me to sit down, that I shouldnt be there. I briefly answered I was about to vomit and if he could leave me alone.
I understand they need a certain control, otherwise in the bigger churches (where maybe 200ppl are taking ayahuasca at the same time), if everybody decided to do something different, it would get out of control, so they need to keep things reasonably organized.. but IF they decide to watch out if everything is going right, then at least they should have the sensitivity of why people are doing what they are and being flexible in their organization, instead of just wanting to eliminate everything that is not exactly like their plans.
One last thing I have to criticise about daime is the fact that the members wear a totally tidy uniform (some special pants, a white shirt and a star in the chest). Maybe its my personal ideas but I really dislike uniforms and what they represent. It gives people a certain sense of identity that they belong to a group, which sometimes may be good, but it also distances the group from anyone outside of it. It is quite clear to me that there is a certain 'superiority' sense in many daimistas in relation to those that dont have the uniform.
In any case, some people really feel good with daime, others not. Everytime I take ayahuasca I have an amazing experience, but I wont be going to their rituals anymore. As for being shamanistic, well, some songs talk about it, and the fact that its ayahuasca makes it somehow shamanistic, but no, it lost the major touch of shamanism. There is a very strong influence of european occultism too, as well as african beliefs and christianity too, so the shamanic part does not appear so obviously. But yeah if you can deal with the lyrics and the rules, you can go deep. Some people can only go deep with this kind of order. I cant.
The indigenous rituals, on the other hand, are much more open. The natives are much more easy going, they trust that people will do the best (so they are not checking whether you are taking too long outside the circle or something, you should decide that for yourself). The chants are sooo beautiful, and if you have a propper pajé (thats the name of the 'shamans' in secret language.. they dont really use this word shaman), then it is the most incredible experience, you really feel the power of the whole situation. They are not just fancy trip sitters and its not just about westerners idealizing shamans (even though this does happen sometimes). They really do have a special effect and control of the whole experience. Having participated with different pajés, I see how much each one can influence totally differently the ritual.
Also the group in each ritual influences a lot the trip, as I said before. There is really some sort of 'chain' that unites the participants during an ayahuasca ritual. There were times where, for example, someone else was vomitting and I could hear the person, and it was as if my soul flew from my body and went with the person, as if I was also there with the person giving this person strenght during his/her own purge. Or as if I felt the 'sins' of the person that was purging. Or once when I was purging in a particular ritual, it really felt like the whole group was there giving me the support. I even saw a person in the side of my vision, standing next to me, that I was sure was real, but when I looked, there was nobody there.
There's some crazy stuff that happens in these rituals. It really feels like magic sometimes, you know, like lord of the rings/harry potter/indigenous myths, with all sorts of weird stuff happening around.
and as for UDV Ive never been, but I have met a couple of ppl from it. They are much less explicit than santo daime, they dont stand out so much, they seem much more quiet about their business. The rituals are a bit different, and there is a highly hierarchical system, where you rise in rank gradually as you participate in more rituals and memorize certain knowledge and 'stories' they pass to the initiates. I cant say much as Ive never been there.