Like any religious community, it is composed of people. And people can do ugly things. But aside from that, there are a few things I sometimes observe that just rub me the wrong way. The Neopagans who have a chip on their shoulder against anything that smells like Christianity; the stupid arguments that occur about use of various terms and who has the right to use some particular label or another; the flawed comparisons to the sciences and derailment into pseudoscience; the phobia of organization and structure to the point it is debilitating and self-sabotaging.
Yeah, I noticed all those things in the neo-pagan group I was involved with informally for a long time. I am not slow in criticizing elements of institutional Christianity, but I wanted to learn about neo-paganism, not crack jokes about other religions all the time. :/ And there was a lot of pseudoscience and the ceremonies were usually slapped together unthoughtfully, though I enjoyed a Kemetic reconstructionist ceremony as a visitor. There was also a lot of hostility to Christopaganism even though one of the most thoughtful, devout members was very Christopagan and always very respectful and kind to me.
On the flip side there are problems in all communities. I still met wonderful thoughtful people. I'd say the negative ones were a minority. And neo-paganism is so broad; there is no obligation to associate with a community one dislikes unlike my current experience with Catholicism. These days my neo-pagan friends mostly practice as solitaries and meet together occasionally for lunch or just to hang out.
Much of my spiritual practice is private, ceremonies and devotions I've created. I'm almost always alone unless a close friend or maybe my sister is present. You can experience or do anything within ethical limits. You don't have to put yourself in a box or put up with ceremonies that you can't connect to. It can be difficult to start from scratch and I often gave up on creating private spiritual practices, but once you find a basic core to adhere to you can let experience and intuition develop your practice to have something coherent and meaningful.
This is my rule of thumb: there are many things I find attractive spiritually speaking from just about any religion modern or ancient. But if you slap together everything shiny you might get overwhelmed with something of little substance. If something is consistent with my core theology and spirituality and it is also useful or grows organically from what I've created, then it can be incorporated, whether it's from another religion (barring issues of cultural misappropriation) or from my own spirit. Otherwise it can be admired and respected from afar in its own context but it's not something I need or even should do.
Cultural misappropriation in particular is tricky. I stopped bothering with incorporating specific elements from other religions a long time ago for that and other reasons. Usually I will adapt something from my own religious background or practice with a similar function or meaning. That keeps me ethical, consistent, and grounds all of my practices in my own Western psyche and spiritual background, keeps me grounded.