There is only ONE manufacturer of unfilmed tubes. And that is L3 (or whatever they're calling themselves these days). Given a thin-filmed tube with similar specs to an unfilmed, the unfilmed produces a crisper, less 'filmy/hazy' view with fast optics, every time. You have a great tube. If you go with a thin-filmed, you'll lose image contrast with fast optics.
My L3 filmless is a great tube with a 0.3 EBI and has delivered 300 objects out of the Sharpless Catalog, but the breed does seem to have improved. Perhaps as marginal as upgrading from a 95 strehl refractor to a 97 strehl refractor, but I am interested in upgrading. So I have been data-mining AR15.com and SnipersHide NV forums.
There are many threads with photo and video comparisons of the various tubes. Keeping in mind these tubes are somewhat like snowflakes, but the consensus on those forums favors the L3 filmless, especially in low-light. Based on the comps I have seen, I would tend to agree.
Of course a prospective buyer should see the comparisons and as always your YMMV.