My concerns:
1. The analog performance isn't really what is specified. I have compared
cheap with quality for "equivalent" hardware in other test equipment and in
general one gets what one pays for.
2. It is a one man shop so promised software enhancements might be slow to
come or fail to arrive altogether.
3. It is kind of nice having a separate screen for signal display and actual
knobs to spin. I am afraid I'll eventually have yet another PC & Display on
my bench which in the end is larger than the dedicated MSO...
I would be very nervous.
$4k will get you a rather nice scope with 4 channel inputs these days.
I use my TDS-420 a lot, and I would NOT want it bound to any PC.