Absolutely a better move, without question! The main reason for it is that Duende uses Firewire, UAD uses internal bus, so it keeps your Firewire bus open and free.
The 2 UAD cards is perfect, it's what I do. The 88RS can do 20 plugs per card. So it beats out Duende hands down.
I can't compared Neve 88RS to Duende: 1- I don't have Duende, 2- different hardware emus 🙂
Compared to LiquidMix, Liquid Mix's EQ and Compressesor emus for Neve are very good, but no 88RS emu so hard to compare. However, of the plugs that match up the UAD is better.
That Neve 88RS channel strip is truly phenomenal.
R