They have a lifetime account promotion going on now, worth getting?

Depends how you look at it.

What I can tell is that I already had their smaller lifetime and waited for that promo to get a larger one.

That plan is worth a little over 3 years sub... As a comparison, the previous cloud service I used (iCloud) I have been using it for a long time... since it was introduced (was it called MobileMe already, or was there another name before that? Can't recall). So, provided Filen does not go bankrupt, I worry not I will get my money worth after those 3 years. Seriously, though, Keep in mind that Filen is a very small and very young company and, unlike Apple, there is possibility the company won't last.

It's a risk I'm willing to take as it really was the closest to what I would call my 'perfect' cloud. Not quite there yet, but close enough for me to use it and closer than any other including Proton Drive, which I'm already paying for (I use their Mail+ plan, which comes with some cloud storage)

Also, note that you can get up to 50GB free storage: 1) by creating your user account using an affiliate link (you may want to check my blog, to use mine) you will get 20GB free instead of the base 10. 2) you then share your own affiliate link to get up to 30GB extra more free. That free storage is then added to whatever plan you decide to purchase and/or to subscribe to, if any. Also, all plans are stackable.

Edit: by all means, take some time to test their free account (there is no real restriction beside storage) so you can see by yourself how well Filen meets your expectations. My needs are really... simple.