I've tested for 5 days; it really helped me to index some pages, not all, though. What I like is that it shows you the pages that are not indexed. It's hard to discover these pages via Search Console. But URL Monitor works like a charm; it is really easy to see what important pages you have that are not indexed. Hope, they'll fix the bug with impressions, and we will also be able to filter pages via impressions. I'm excited to see new features like being able to see which external URLs are not indexed, and being able to index them, would really help with link-building efforts.