These are both second volumes (Romophone Vol. 1, 3/94; Nimbus, 5/90), so choice depends partly on what you already possess, partly on how much you want. Romophone's Vol. 2 on two CDs carries on from June 1920, ending (still in the pre-electrical period) in September 1924. Nimbus's Vol. 2 provides an overall view on a single CD, starting in 1917 and carrying through into the electricals, up to one of the last, of 1930. A complete Galli-Curci, very desirable in many ways, would incorporate some items (but not all that many) that you may never want to hear again, though so far I have found in these volumes only one that comes within that category, the inane Pretty mocking bird by Bishop, and even that might possibly be useful some day as an exhibit, or perhaps as a humour restorative when too much of 'the news' makes one wonder whether there will be anything to laugh at ever again.
The other factor is the quality of transfer. The Romophones are excellent: good, clear sound, reliable speeds and pitches, the work of Ward Marston. Nimbus are what is hedgingly called 'controversial'. That is, for every youngster who suddenly sits up and says ''I never knew these old records could sound like that'', there is an expert who can scarcely conceal the pity and incredulity provoked when someone such as myself admits to frequently playing them with pleasure. Three purely subjective facts arise out of this present listening: on two occasions, like the newcomer instanced above, I sat up during the long session, with surprise at a sudden vividness—this was once when switching to Nimbus to compare the first of the Trovatore arias, and then at the start of the same disc with the sound of Lakme's Bell song—and the other fact is that I have never enjoyed the Hamlet record so much as now on Nimbus, or thought it so fine a performance, the sound having previously seemed boxy and over-bright with the hardness of those early electricals.
In both sets of transfers I found a certain point at which the ears began to complain, and take it that this is inherent in the recordings (on the Romophones it occurred at loud notes in the top A flat to B flat area; on Nimbus, if I'm not mistaken, just a little lower). The stunningly good recording and transfer on Romophone of the The golden cockerel and Sadko solos show up a limitation on Nimbus, and I don't doubt that the limitations are real enough. All this is marginal anyway. The real point is that on all of these issues is some of the most delightful singing to be found on record. Try the Adam Variations (''Ah, vous dirai-je, maman'' from Le toreador—Romophone only), the aria from Les pecheurs de perles, the duets with Tito Schipa and (Romophone only) a charmer of a trifle, Serenade by Pierne.'