Do the Isolation Transformers protect system

Hello Everyone,

I wonder if an isolation transformer protects the system from surges,spikes etc like most of the other power conditioners do.
I use a custom made 1.5KVa isolation transformer where I plug my power amp,preamp and Isoclean power strip.
Then I plug my cd transport and DAC in the power strip.
Since the Isoclean strip does not offer any protection I only rely on the transformer for system protection.
The person who built the transformer claims it protects
the system from power fluctuations,however I would like to hear from those who have experience/knowledge about such a transformers.
Isoclean produces isolation transformer of highest quality,which paired with their top of the line power filter sells for mega $$$ and is usually used in very high end systems.
I doubt owners of such a systems would not care about protection.
Your help/thoughts would be aprreciated.
Thank you.