I agree with Ralph Moore's views on the work but have not heard the Naxos CDs. Not even the two long scenes included in Toscanini's 1948 La Scala celebration of the composer convinced me. If the sound had been better I might have a different opinion.
The best version I heard was the Turin broadcast concert 1975 wirh Prevedi, Ligabue, Baldani, conductor Gavazzeni. This message is to encourage anyone interested who still uses LPs to investigate it on three MRF discs (161-S). It's in stereo and surely taken from a broadcast. There have been later issues but the LP box has the most ambitious documentation I ever saw from a "pirate": libretto with English translation; the libretto for the fifth act which Boito never set; 270 fottnotes to the libretto explaining and sometimes graphically illustrating Boito's erudite terms; articles on Boito and on "the historical Nero"; and a biblography of about 50 scholarly sources. Following the libretto while listening I was so preoccupied with all this that the music did not matter much, which shows up its weaknesses even with good pressings of a good performance. That it's now decades since I last played it reinforces this.
Curiosity about the work was strong when it was new. Even my home town Stockholm's Opera presented a lavish and well-cast production in April 1926. There were 25 performances until November 1927, a lot for those days. Ljungberg (later Thorborg) and Wettergren in the leading female roles and the staging as such probably attracted more than the music. But the leading baritone Einar Larson recorded Fanuèl's two arias on a 78, so it was obviously considererd an important new opera.