If you're not using VWO and want to be able to view pages in the eyes of different user agents quickly, there's a bunch of Chrome and Firefox user-agent switcher extensions out there, such as this one: https://chrome.google.com/webstore/detail/user-agent-switcher/lkmofgnohbedopheiphabfhfjgkhfcgf
Simply load the page, choose your agent (may need to refresh) and hey presto. Doesn't review your page like VWO would, but you'd be able to see yourself any glaring errors.
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