Sherwood only tests receivers so the only must have mod is the RX AGC ND6T flavor.
All the hot receivers are SDR and direct digital sample (flex, and Anan) thought the
7300 (also a SDR) is up there.
Of the radios using more conventional analog techniques two of mine the Atlas
and the TT 340 are fair comparisons for single conversion. The Tentec is the
only low IF with selectable filters at 9mhz to digital IF unlike those with VHF
first IFs. Of those three the listed radios Tentec Eagle, Atlas 215X,
Tentec 340/Triton on the list in that order from best to worst. This radio
without AGC is not likely to be above any of them. Also the Atlas 215X a
1976ish design is a diode mixer front end like the uBitx with and AGC in
the IF and a diode mixer for product detector so it would compare
closest to the uBitx.
Note: In dollars none of those radios even as used/broken approach 100$
and new were much more expensive by many times.
Comparable transceivers in the power class is FT817, IC703 and
Tentec Argonaut QRP series such as the used Argonaut model 505
that I use very regular for the 5W QRP level.
Reasons that is likely:
RX overload point, the limit here being the diode mixer.
Filters First (45mhz) is wide and the second is fixed at SSB bandwidth.
close in and wide overload
Phase noise from the LO systems (LO1, LO2, BFO).
Sensitivity is never an issue.