Some of the standard guides can be very, very good. Like the current HW ones. If they fit the spring well, they work as good as anything. And even better if doubled up with a top hat.
Steel ones will offer greater longevity. Harder and more time consuming to machine up though, reportedly (I don't have a lathe so don't make them).
And I'd guess that due to the difference in materials, resonance etc., a synthetic one will be quieter, although a properly fitting steel one in conjunction with proper lubrication will perform extremely well.
Hope this helps.