I recently got my hands on a nasty bargain: a 135mm f/3.5 Jupiter-37AM and a 58mm f/2 Helios-44-2 lens for the grand total of $9.00 (actually $17.12 including US shipping, and another 518 pesos for US-Philippines forwarding via Johnny Air Cargo "your friendly e-bay enabler!")
I must say the Helios-44-2 sets a new low in lows in the build quality department. Light years worse than the 1960's Pentax Takumars, significantly worse than my early 1980's East German Zeiss, measurably worse than my early 1990's Russian Jupiter-9 and Mir-1v. Seems after glasnost and perestroika the build quality of Russian lenses actually went up.
It's made of some grotty aluminum alloy (the filter ring was dented, when I tried to straighten it with some pliers, little aluminum bits fell off). The preset aperture mechanism wobbles perilously, the black paint is coming off, and it projects this air of mechanical cheapness. Kind of like a jeepney..
It does have that cool "Made in USSR" label though.
Anyway I just did some sample comparison images, these are by no means definitive.
Rollei 50mm f/1.8 Planar, Singapore, wide-open:
Pentax Super-Takumar 50mm f/1.4, stopped down to f/2 (and yellow cast bleached out with UV light):
Pentax SMC-A 50mm f/2:
Helios 44-2 58mm f/2:
In the sharpness department, the Super-Takumar beats them all, as it's already stopped down one stop while all the other lenses are wide open. It also doesn't have the "bright outline" bokeh that all the other lenses have, it does however betray its non-cool six-blade diaphragm in the OOF highlights.
In terms of overall image quality, I kind of like the Rollei (can't explain it), there's something about that Zeiss quality.. but it's ugly, I took the lens unit of the Planar and stuck it into the (plastic) focusing helical of a Fujinon 55mm f/2.2 which I destroyed, as Rollei SL35 lenses have too short a registration distance for K mount.
But the grotty Helios does show some of that creamy Zeiss bokeh (it is after all a clone of the Zeiss Biotar). Maybe I will always use it stopped down a bit (it has a super round diaphragm like the Jupiter-9 and Jupiter-37AM).
Here's the Frankenstein Rollei at f/2.8 with the Helios-44-2 (that 16-45mm f/4 ED AL makes a nice pedestal for the ancient lenses!)
Still very nice, circular OOF highlights, creamy bokeh.. I think I'm gonna like the Helios-44-2, it's like a shorter Jupiter-9.