I'm surprised at how good the cheap preamps and converters all sound. And it may be that the problem with the cheap preamps and converters is that they will start to sound tiring after a while of listening or that when you start stacking them in a mix they get to be a bit either harsh or muddy. But one at a time, especially when you're not A/B'ing them against very expensive gear, they sound quite nice.
Above is a test of the Neve 1272 mic preamp vs the internal preamp on the M-Audio 2626. It's an unfair comparison and you don't need to do a double-blind study to realize that wow, the Neves sure do sound nice.
I actually through a scientific evaluation out the window and went and EQ'ed the tracks. Individually. Just to make them each sound very nice. The Neve, of course, has the low-mid thump that had to be cut out. But I added a bit more in the 4K range to each of them (although the center frequencies are somewhat different.)