For me, speed ratings are the holy grail and they get more and more powerful as times goes by as people are getting lazier. Especially people that use systems!
Ignore all weight adjusted ratings as they are a complete load of tosh.
Personally I think they are far more valuable on the NH then they are on the flat! A horse has a style of running so to say it is more about tactics then a horses speed is simply not true as I've given a horse near enough the same rating for 5+ runs regardless if at a glance the race appeared to be run slow or quick.
They form the basis of 99%+ of all of my bets and always will and I've been a profitable punter for 8 years!
Speed ratings will never get a great reception here as this site is geared towards systems but, I think if you asked the same question on a more form based forum you would get a completely different answer.
No offense intended but, compilers place huge emphasis on SRs and for good reason. They will tell you everything about an exposed runner. Distance, going, track, performance pattern etc
Some people see things that are and ask, Why? Some people dream of things that never were and ask, Why not? Some people have to go to work and don't have time for all that ...
George Carlin