1) López-Corredoira & Gutiérrez (2012, RAA, 12, 249): Extremely luminous QSOs exist at high redshift but they are absent at low redshift. Our analyses show that it is not due to any significant evolution of black hole masses or Eddington ratios for equal luminosity QSOs, so the problem can be translated into a "Why are not there QSOs with very high black hole masses at low redshift?". 2) López-Corredoira & Perucho (2012, A&A, 544, 56): The MOJAVE survey contains 101 quasars with a total of 354 observed radio components that are different from the radio cores, among which 95% move with apparent projected superluminal velocities with respect to the core, and 45% have projected velocities larger than 10c (with a maximum velocity 60c). Relativistic Doppler boosting explains these apparent anomalies, but it requires a huge average kinetic power to produce such powerful ejections: ~7×10^{47} erg/s, a significant portion of the Eddington luminosity and on the order of the bolometric luminosity. This amount is much higher than previous estimates of kinetic power on kpc-scales. 3) There are many other pending problems in QSOs in the literature (review at López-Corredoira 2011, IJAA, 1, 73): the different structure of the clouds along the QSO's line of sight and their tangential directions; the spatial correlation between QSOs and galaxies; inconsistencies in the AGN unification model; etc.