If I were ever seriously worried about losing stuff, I wouldn't be using nightlys But I still appreciate the effort to not break stuff.
Small bug with the indentation guides, the active ones don't always show up on the whole column. Screenshot is below.
Additionally, as some people point out the active one shows up one tab higher than where they should. My screenshot shows that too.
I'm torn on this. On the one hand, I think it's smart to do that for normal statements. However, for lines that are indented, (like for loops, html tags) I hate it. Maybe you could use the grammar indent rules to determine if it should show the active guide one column higher or at the current column, if that makes sense. Like, if the indent rules say dont indent this line, then do what sublime does now. If the indent rules say indent the next line. then show the active guide at the beginning of the text, like the beginning of the for loop, not two spaces before the for loop.
Lastly, one last tiny bit of polish that would be nice if you're up for it. If a line is indented say 8 spaces and I click at column 2, it will draw an indent guide at column 6. I think if I click/arrow key before the first non-whitespace character, it should draw the indent guide where the cursor is. If I click after the first non-whitespace character, it draws the indent guide at that first non-whitespace character.