Ive tried many meditation timers on my iPhone over several years, and Samsara is by far the one I most prefer. It is feature-rich while remaining simple to use, with a beautiful interface that is easy see without any unnecessary clutter.
The many bell sounds for starting and ending a session are very much to my tastes, and the ability to set the number of chimes and the interval between each allows me to customize the experience to my exact liking - with even the ability to make each chime in a set get gradually louder (which is how I like to end my sessions). Warm-up and cool-down times can be included as well as arbitrary chimes mid-session - along with many other thoughtful features.
One can save any number of presets and these are very easy to set up. My only feature request (at the time of this review) would be to be able to copy an existing preset so I can use it as the basis for a new one. But this is only a small concern since the presets are easy to establish, and I only make new ones occasionally.
While this app is more costly than many of the others that are similar, it is well worth the price for its elegance and practical use. There are no in-app purchases or social media components, and for that I am very thankful. When I sit (zazen is my practice), I want a tool that serves to time my session with simplicity and beauty and without the phone getting in the way. Samsara does this for me with excellence. I cant recommend it more highly.