This thing is excellent.

I've been editing video for over 30 years used many online editors and I don't think I've found one this fast and robust. Its also probably the first one I’ve tried that has me planning to add team members and expect to use it in production.

Here are my impressions after using it for a couple of hours

Uploading to the library was very fast

It even accepted some more obscure formats that I tested it with.

The timeline is easy and a joy to use.
It handles multiple layers with ease and is very responsive to changes.
Cutting, shifting and layering is as easy as can be, fast and very accurate. Working on the timeline is very pleasant and efficient. That’s pretty rare with online NLEs

Most online editors are not very accurate and edits made are often ‘approximate’ and don’t play back exactly as you made them. There is no trace of any of that glitchiness or that feeling of pulling clips through mud that you get with a lot of online NLEs.

The audio capabilities are powerful. You can see an audio waveform of your audio which makes it easy to edit to the beat visually and even visually find your in out points for cross-fading, etc. Audio is also fast and responsive.

Use multiple layers of voice over and music (most online apps can handle 1 or two if you're lucky)

I even did a test of a luminance key (removing black) and it performed admirably.

All the above can be done quickly in the easy-to-use editing interface

I love the groups feature which makes it easy to, well, group clips to move them allowing you to make more complex sequences without your project becoming unruly

I'm not giving up my offline edit suite (don’t expect this to replace a high end edit suite, though for most common tasks it comes pretty close) but don't overlook the most important feature of Flixier. You can collaborate with multiple people around the world.

Record your video and Helsinki in the morning and have your friend in Perth Australia edit six new versions of it for your various social media accounts while you sleep.

One person can do a rough edit and someone else can polish it, no need to share , upload, download with DropBox and sync your exported projects, it’s all just there, ready for you when you want it

Upload your logos, branding, bumpers etc to the shared library and anyone you give access to can produce work that has consistent visual elements and branding

Make a copy of a project and swap out the footage to quickly create new videos

Unique to Flixier is that It can import JSON After Effects templates for Motion Graphics (titles, lower thirds, info text, etc) which opens up the possibility of importing third party presets

I don't see a problem with the amount of export hours if you are using this to produce promos, ads, social media clips, video updates, it's hard to imagine running out of time while producing quality material, and if video is a major part of your business, stacking multiple codes is a no-brainer