  We describe the results of a survey of the UV absorption properties of the
Boroson & Green sample of AGN, which extends from the Seyfert (M_V ~ -21) to
the luminous quasar (M_V ~ -27) level. The survey is based mostly on HST
archival data available for >~ 1/2 of the 87 sample objects. Our main result is
that soft X-ray weak quasars (SXWQs, 10 AGN with alpha_ox<= -2) show the
strongest UV absorption at a given luminosity, and their maximum outflow
velocity, v_max, is strongly correlated with M_V (r_S=-0.95). This suggests
that v_max is largely set by the luminosity, as expected for radiation-pressure
driven outflows. Luminous SXWQs have preferentially low [O III] luminosity,
which suggests they are physically distinct from unabsorbed AGN, while
non-SXWQs with UV absorption are consistent with being drawn from the
unabsorbed AGN population. We also find an indication that v_max/v_BLR
increases with L/L_Edd, as expected for radiation-pressure driven outflows.
This relation and the v_max vs. M_V relation may indicate that the
radiation-pressure force multiplier increases with luminosity, and that the
wind launching radius in non-SXWQs is ~10 times larger than in SXWQs.
