Like all victorious powers of WWII, the Soviets captured and tested a few examples of the revolutionary Komet. As far as is known, the Soviets had at least one B model, and an S model two-seater. Very little is known about the single-seater. It is reported it was flown as a glider, lacking the special fuels.
Shamus Reddin of the Walter HWK 109-509 Site sent a scan of what's probably the best photo of the Soviet Me 163B. Source is a 'Red Luftwaffe' article in Flypast, April 1990 issue. The presence of the DF loop on the spine is remarkable. In the 'Red Luftwaffe' article the photo was shown mirrored, but the presence of the pitot tube, and the absence of canopy hinges shows that this really is the left side.
Richard Aigner reported the following on YouTube: Captured German jet aircraft in the USSR. At 0:18 we can see a Soviet pilot boarding a Komet, and at 1:13 a towed take-off is shown.