I have the free version (a year now), but I personally use with Magic Bullet Looks. I'm still using an old version, 2.0.4., and while it can't load a LUT, there are hundreds of .ls3 files out there.
But the price of getting the latest version MBLooks is out of my range. 3D LUT's paid version is amazing how you can adjust the color parameters so easily.
I do like how you can preview a LUT before applying it. Saves a TON of time.
This one's been around a while, and it is on my system. The preview capability is nice, but the time it takes to load all of that junk from the internet, well, ... not really worth it for me.
I downloaded that free 3D Lut Creator OFX plugin a while back. It corrupted Windows Defender when I first used it in Vegas. I didn't know it at first. It was after running SFC and DISM -- as I recall -- that I discovered the corruption. After recovering, I ran that plugin again, and I could hear the hard drive zipping around making changes in less than a second. I ran SFC and DISM again and sure enough Windows Defender was corrupted again. It didn't seem corrupted, but being cautious I didn't use the plugin anymore.