S-TEC options

[Pat Rolfes]

After 3rd trip to avionics to try and fix my VFR only 400a autopilot, I'm throwing in the towel.
I have never had it as a "coupled" autopilot. It was always hand flown using DG knob and alt. hold or control wheel altitude climb/descent.
With that history, I am having trouble determining my needs vs. expenses between S-TEC 30 or 55.
Anyone out there with pro or con arguments for either.both?
Thanks,
Pat