Muse was a pioneer in home use brainwave sensing and I certainly learned a lot about the brainwave correlations of meditative states using Muse, but it required a third-party app to actually see a graph of the brainwaves and this involved several steps.
When I found Flowtime, I was happy to see that all the data, including brainwave graphs, appear right in their app. In addition to brainwaves, Flowtime also tracks heartrate, HRV, coherence, and levels of attention (a combination of beta and gamma waves) and relaxation (a combination of alpha and theta waves). I find these additional metrics very useful to see the fuller picture of how meditation affects body and mind. (You can see a livestream of these metrics in the video I've posted with this review.)
I've found Flowtime to be reliable and accurate over the years that I've used it. It has frontal sensors which contact with the skin of the forehead making for clean connection and they filter gamma waves at 45 Hz to guard against artifacts.
Recently, they have upgraded their app to include biofeedback (a pleasing singing bowl sound) for a Flow state, which I would describe as a relaxed, present, attentive, and immersed state, where my body is relaxed, emotions are calm, and mind is quiet. I prefer the Flowtime biofeedback because it just gives you a pleasant sound when you are in the target state but is silent otherwise. (In contrast, Muse biofeedback gives you storm sounds when you are in a state other than their target calm state, which can be disconcerting and might make you think you are doing something wrong, when you might just be focusing attention in another way.)
Finally, Flowtime has just upgraded their headset to make it more flexible to fit a variety of head shapes and more durable and comfortable. This upgrade is still lightweight, which is another feature I like.
All in all I highly recommend Flowtime as a helpful tool to support and fine-tune your meditation practice.