Fi is reasonably well known, yeah. They make what is generally regarded as the best infinite baffle driver for the money, the IB3. There have also been quite a few discussion threads about their SSD and Q series drivers, as these series provide for a reasonably inexpensive system that, with proper EQ and L/T circuitry, can perform well down into the last octave when used in multiples. However, they were tested by Ricci at www.data-bass.com and were perhaps...less impressive than expected, imho.
Another thing about Fi is that they are the build house for some ID sub manufacturers, which means that they likely produce quality and reliability. The problem is, their production has not been able to keep up with demand in the last year (for whatever reason, supply side or demand side), and they often take 6+weeks to deliver to consumers, and longer to deliver to vendors. Frequent missed delivery dates has plagued them, of late.
So, while Fi builds well-regarded drivers, they're not especially good at getting them to commercial customers or consumers in a timely manner. We'll see how it ends up for PSA, but I wish them the best of luck and hope to hear some of their products soon.