Having fired a couple, filmed quite a few, and analysed many others; I concluded that both Firestreak and Red Top were very effective weapons for their era - considering the constraints in design and manufacture (valves and clockwork motors).
The IR detectors and homing head technology probably led the world – I recall reports of an incident in the US involving difficulties in returning a F/S head to the UK.
Air-to-air weapons development advanced rapidly in the post war years, as such F/S & R/T soon appeared to be less capable than competing systems. This might have been true for maximum range or angle-off capability, but there were many mitigating advantages, notably that F/S & R/T worked (high launch success rate), they were accurate, and with their intelligent fusing systems and large warheads ensured a high probability of a ‘kill’.
Pretty much in a Nutshell.
I worked a spell at MPC Valley, first in the Missile Site itself and later in Operations; the MPC was not simply each squadron shooting off a few missiles every year but also a technical evaluation of missile reliability and home base maintenance (missiles and aircraft systems); in fact, the whole package of maintenance and pilot capability went through the hoop with generally very impressive results.