Every provider sounds fine in a brochure. The words are soft on purpose: comprehensive, powertrain, peace of mind. The contract is where those words get narrow. Before you line up providers against each other, pick one imagined breakdown and walk it through every form you have.
Write the breakdown down first
Choose a plain failure your car could realistically have, such as a water pump, a steering rack, or a sensor that feeds the transmission. Write it on a sheet by itself, along with the make, the model year, the mileage you are at now, and the shop you would use. Keep the scenario identical for every provider. If you let each sales rep describe their own version, you are back to comparing sales pitches.
Find the lines that decide the claim
For each form, locate five things and mark them the same way: the covered parts list or the exclusion list, the definition of the failure that triggers coverage, any wear or maintenance exclusion, the pre-authorization rule, and the payment rule that says whether the provider pays the shop directly or reimburses you. Then ask whether your breakdown appears on the covered list, falls under an exclusion, or is caught by a phrase the form never defines.
Read the gaps, not the headline
A form with a named component list can be narrower than one with a catch-all clause, or the reverse, depending on how the exclusions are written. Note every place where the form says nothing at all. Silence on a point is a question to put to the provider in writing, not a yes.
Compare the answers, then the paperwork
Build a grid with one row per form and one column per question. Only after that grid is filled should you weigh anything else, including the sales pitch or the friendliness of the phone line. The published figures on this site can help you narrow the field, and the providers that publish a sample contract list is the easiest starting point, because you can run this exercise before anyone asks for payment details.