A tricky one really because my favourite match with the 92/90 was the original CD3, which in many ways I preferred to the CD3.5. Trouble with the CD3 is that while it used the wonderful Philips CDM9/44 mech, these are now long gone, so if one failed you’re down to scavenging for parts. Also, the old TDA1541A crown and double crown DAC chips can eventually fail or go noisy, and while I think that Naim can still replace them, they aren’t cheap. However, it’s a hugely characterful and entertaining player - maybe too much so for anyone favouring absolute neutrality as a priority - that’s usually available fairly inexpensively secondhand.
The CD5 is basically very similar to the 3.5 and also uses the same VAM1205 mech.
The CD5i is a step down in my opinion. The CD5x is in many ways, a good step up, particularly with regard to its neutrality and space, you also get HDCD too, however great as it is, it’s just not quite as much fun as the CD3…