The safest bet for browsers is Chrome, since that is what we use in development. However, we test on Safari, Firefox, and Microsoft Edge, so those are pretty safe, too. Internet Explorer (IE) is known to have issues and should be avoided, since it does not take advantage of some of the latest web technologies (at least not easily). Whichever browser you choose, please make sure the version is up to date, since AWdb takes advantage of the latest technologies.
You can use any device that runs a web browser, however if it has a very small amount of memory or low processing power, you will notice the app running slow. Also, in order to take pictures within the app, you need a sufficient amount of memory or the app will crash. Whatever device you have, give it a trial run to see how it works. If it's slow, compare it with other leaders who have an iPhone or iPad, since we know those run the app well. That should help you determine if it's a network issue or a device issue. (If it runs well on someone else's phone, but not yours, it's probably your device. If it's slow even on laptops, it's probably your network connection.)