Ok nga yang 540C sir. Buti may stock pa sila diyan sa Marquee (or display unit ba?). It's a very revealing player for the price.
Personally though, parang sulit ang improvements ng 550C over it kung di masyado malayo ang presyo. I think the 550C is at the cost/performance sweet spot, since it actually outperforms the 640C in many aspects (except with outright detail and separation)... at least to my ears.
To me, the 550C and the 650C get dangerously close to the 740C in musical capability. The 740C just gets a win because of its technical superiority and features.
The 550C and the 650C are less forward-sounding (against the 740C), and have a bit more body on each note. However, the 740C can present the stage with convincing depth and layering, and can build very defined images of each instrument.