I have been using Omnifocus for a couple of years now, both on iPhone and iPad, and can tell you that it has been a very satisfying experience. I use their included Omnisync service and have experienced no data loss, and other than having to wait a few seconds for the devices to sync, it has been like using one device. This is a professional level tool, and saves you the money you spend in no time. With the advent of being able to create and manage perspectives it has become even more powerful! I cannot say enough about this product, it is worth every penny!
springbuffer about OmniFocus 2, v2.0.2