I've been using across for several years. However, actually I do not like this CAT tool. To be familiar with this tool, I mapped some keyboard shortcuts to match the Trados ones using AutoHotkey (Please refer to this post for customizing keyboard combinations using AutoHotkey.) Recently, I took a big job which related to translating some html files. Of course, across supports a 'spell-check' feature. But it's not satisfactory. I could perform full spell check using the 'Preview' feature after the translation was complete. It's very simple. To preview the source or target file, please choose "Tools > Preview" on the menu bar.