If your room is truly light controlled, IE no white surfaces like a white ceiling then you want a high contrast projector. Save your money up for a Epson 5050ub, Sony or JVC. If you have a white ceiling and have no use for the power lens shift of the 4010/50 I would most likely opt for the BenQ. It won't give you any better black level then your HT1070a but hits high marks for everything else. The Epson may have better contrast but not sure as I would love to see a side by side shoot out between these two in a good blacked out room so contrast isn't compromised by white surfaces. Note that the 4010 is the identical projector without the spare lamp in a white case.
"Smart enough to know better, to old to care" ------ Dedicated Bat Cave Home Theater, JVC RS49U/Mitsubishi HC7900DW Projector, 110" 16:9 Jamestown screen with variable power masking for CIW 2.50:1 to 16:9, Marantz 7009 with 7.1.4 Atmos with Ohm mains,3 DIY Subs (2 15" (1 ported, 1 sealed and a 12" 4th order bandpass), 1 DIY butt kicker, Custom Built HTPC, 18TB DroboFS NAS