I started doing Spectrum pretty recently so I've only had experience with v4 but I've really been impressed. I'm planning on using it exclusively going forward.

The software on the desktop is a much better experience than anything I've used in the past and better than using a browser. I think the mobile app is good but don't use it on a daily basis so there may be shortcomings I'm not aware of. They have added the motion search feature to the app so you can draw a box and it will return search results with motion in that area, which is pretty cool.