I'm glad you like them so far; I hope you will continue to like them for a long time. They really are nice strings, and, as others have pointed out; their initial cost, amortized over their long life (provided you take reasonable care of them, becomes stupid low.
Personally? Out of the 24 basses in my herd, all but 2 wear flats. Out of those, only one wears TIJFs. Although I do like them, there are reasons why they aren't on more of my basses...
- I think they're too flexible to play with a pick. Yes, I know that people disagree, and from their POV? They're probably right. But, the stiffness contrast between TI's and the many other flats I play with a pick, is quite pronounced. If the bass with the TI's ('96 Alembic Epic) was my only bass, or if all my basses wore them, there wouldn't be a problem. But, the technique adjustment required to play the one bass with TI's, compared to the 16-17 others - with really stiff flats - that are played with a pick 100% of the time, is more than I care to deal with. So, it's the only bass that gets finger picked - all the time. Which, for what I use the bass for, isn't a problem at all.
- IME, TI's are among the roughest flats I've played. And, over 50+years of playing flats, I've played an awful lot of them. They certainly aren't the roughest - IMO, the Roto 77LD's are - but they don't bother me. In fact, the minute gaps in the winding that makes them "rough" is part of what makes them so flexible. Still, silky smooth they are not. Currently, in my herd that crown goes to the Galli Jazz Flats on my EBMM 4HH Stingray Special. They're smoother than wet ice. And, after 3 years on the Alembic, those TI's haven't gotten the least bit smoother. But, as I said; by no means a problem.
- Their tone. I class TIJF's as firmly in the "modern, middy flats" family. Which is fine; they work great for some of what I play, but... so do some other flats I use. Particularly Fender's 9050Ls, which, IMO, sound an awful lot like the TIJFs. A lot cheaper - and for me, they also work much better with a pick. Yes, of course I tried the Fender's on the Alembic; maybe it's because of the active electronics, but the TI's just sound better on that bass. As for the majority of what I like to play? Sorry; flats with more of the "Old School Flats" tone work much, much better. TIJF's just don't have the bottom end to do well in the "pretend it's an upright bass" territory that is '50s-early '60s Rock, Rockabilly, C&W and Blues.
So... much as I like TIJFs; for me? I have to say that, nice as they are, they're just not the Alpha & Omega of flat wounds. In their tonal range, though - they are
awfully hard to beat...